Absolute dating of the European Neolithic using the 5259 BC rapid ^14C excursion

Domain: earth_science
Published: 2024-05-20
Editorial outcome: minor_revision

Abstract
Abrupt radiocarbon (14C) excursions, or Miyake events, in sequences of radiocarbon measurements from calendar-dated tree-rings provide opportunities to assign absolute calendar dates to undated wood samples from contexts across history and prehistory. Here, we report a tree-ring and 14C-dating study of the Neolithic site of Dispilio, Northern Greece, a waterlogged archaeological site on Lake Kastoria. Findings secure an absolute, calendar-dated time using the 5259 BC Miyake event, with the final ring of the 303-year-long juniper tree-ring chronology dating to 5140 BC. While other sites have been absolutely dated to a calendar year through 14C-signature Miyake events, Dispilio is the first European Neolithic site of these and it provides a fixed, calendar-year anchor point for regional chronologies of the Neolithic.

Introduction
The Neolithic period in western Eurasia marks one of the most important transitions in human social, economic, and technological history. This transition, which lasted several millennia, is chiefly characterised by the appearance and gradual adoption of agriculture and animal husbandry accompanied by increasing social and material culture complexity. The appearance of the first Neolithic communities on the Aegean coasts and in Northern Greece, and hence in continental Europe, is dated to around 6500 BC1–6. The expansion of the Neolithic settlements further inland to the North was a rapid process7. Consequently, their precise dating is essential to our understanding of neolithisation processes in Europe and critical to assessments of the environmental footprint of the new farming subsistence practices.

However, the temporal resolution of archaeological and environmental proxies in the region is highly variable, producing significant discrepancies between various chronological and terminological systems that deal with the periodisation of the Neolithic8. The combination of tree-ring dating (dendrochronology) and rapid 14C excursions has been previously used for the absolute dating of sites only from the Common Era9–12. Here, we present the absolute dating of the 6th millennium BC lake-dwelling site of Dispilio in Northwestern Greece. Our results may provide the basis for absolute dendrochronological dating of other Neolithic sites in the region (Fig. 1).

Tree-rings enable high-resolution dating, the possibility of annually resolved climatic reconstruction, and multidisciplinary chronological synchronization, often to a single growth season of a specific calendar year13. Until recently9, dendrochronological dating was possible only against reference tree-ring chronologies, which are continuous, unbroken sequences of tree-ring width records extending from the present back to the distant past. Based on known dates from living trees, calendar-years are assigned to tree-rings and then extended into the past using climatically constrained, region-specific, continuous tree-ring growth patterns. Long-term concentrated efforts in search for old wood samples have resulted in the construction of long tree-ring record extending back many thousands of years; these are widely applied to dating14–16 and paleoclimatic analyses17,18, shedding light on past human and environmental interactions. However, these records are geographically limited and rare. Moreover, many prehistoric tree-ring chronologies are only approximately constrained on a calendar timescale through conventional 14C wiggle-matching and have no absolute calendar anchor.

This limitation can now be overcome by a new hybrid form of dendrochronological and single-year radiocarbon analyses. Annual measurements of 14C in dendrochronologically dated Holocene tree-rings have revealed the occurrence of rapid short-term spikes in atmospheric 14C concentration in the past19,20. These 14C spikes, also called Miyake or solar energetic particle (SEP) events, are uniquely suitable for absolute dating of any wooden objects with detectable annual rings9,21. The discovery of these short-term events has also led to a proliferation of annual 14C measurements on single tree-rings, now spanning several millennia22–24. The mechanisms behind these 14C events are still debated25,26. However, a broadly accepted explanation is that they result from coronal mass ejections from the Sun25,27–29. These lead to a surge of SEPs colliding with the Earth’s atmosphere, which increases the production of cosmogenic radionuclides22,29. To date, only five events19,20,22,30 involving an atmospheric 14C increase of ≥1% within 2 years22 have been confirmed. Of these, the two most recently discovered events are in the first half of the Holocene, in 7176 BC and 5259 BC22, offering now the possibility for absolute annual dating of wood from the 8th and 6th millennia BC using annual 14C measurements.

In temperate climates, wood and other organic materials can be preserved only in very stable conditions, as in low-oxygen waterlogged sediments at wetland archaeological sites31–33. Excavated wetland sites are very numerous and often excavated in Central Europe, and several wetland sites have also been found and excavated in south-eastern Europe, notably in the south-western Balkans34–40. Dendrochronological work on these sites has led to the construction of several tree-ring width chronologies, which were approximately fixed in time by 14C wiggle matching41,42. Dispilio on the shores of Lake Kastoria in north-western Greece is an archaeologically significant prehistoric wetland site in the region, considering that it is the only “pile-dwelling” settlement in the Balkans to be systematically excavated over multiple years and over a large area. Numerous lines of evidence have yielded detailed results on the site’s geoarchaeology39, palynology43,44 anthracology45,46, woodworking technology47, and material culture48,49 (Fig. 2). The approximate calendar-age chronology of the site has been established through radiocarbon dates, mostly performed on charcoal samples39,50. Charcoal is susceptible to the so-called “inbuilt age”, which may produce overly old radiocarbon dates. The calibrated date-ranges point to settlement phases between the later Middle Neolithic (~5600 cal BC51) and the Bronze Age (~2100 cal BC50). The excavations at Dispilio have also yielded a great number of wooden remains, with over 1200 mapped construction elements in the site’s East Sector to date (Fig. 1c). Yet despite the extensive remains of wooden construction elements, no systematic sampling and no dendrochronological studies have yet been conducted at the site. The value of developing a precise and accurate calendar-dated chronological sequence using these wooden remains is further enhanced by the fact that the site of Dispilio has yielded more than 1700 complete and fully reconstructed ceramic vessels: one of the largest complete Neolithic ceramic assemblages in Europe. Tree-ring dating at Dispilio can therefore be used in conjunction with the ceramics typology network to underpin and improve the relative chronology of the entire region.

In 2019 a large-scale fieldwork campaign took place at Dispilio’s Eastern Sector (Fig. 1d). Over 900 piles were mapped, of which 787 were sampled for the first dendrochronological analysis. The results provided a ‘floating’ oak tree-ring chronology spanning 120 years and an overlapping juniper tree-ring chronology spanning 303 years. However, this dendrochronological record could not be dated absolutely because despite the existence of several millennia-long tree-ring chronologies in the Eastern Mediterranean17,52,53, none extend back to 7500 years. Here, we overcome this limitation by using the combination of dendrochronological and single-year radiocarbon analysis (Fig. 3), placing the last ring of the Dispilio juniper chronology at 5140 BC. To our knowledge, no calendar-year absolute dating has been achieved yet for any other Neolithic site in the wider Mediterranean region.

Results
Dendrochronology
Wood samples from Dispilio were first sorted by genus, then measured and cross-dated into tree-ring width (TRW) chronologies. Then, individual tree-rings from the cross-dated wood samples were sampled for 14C measurement to identify the 5259 BC 14C spike in the juniper tree-ring chronology, which provides the absolute calendar-year placement of the tree-ring chronology. Of the total wood samples from the 2019 fieldwork (n=787), 23% were cross-dated into two master tree-ring width (TRW) chronologies. Wood anatomical species determination revealed that the majority of the wooden piles came from juniper (Juniperus spp., 62%) and oak (Quercus spp., 21%) wood. The third most abundant genus was pine (Pinus spp., 17%), which was not suitable for dendrochronological cross-dating given the low number of annual ring on most pine samples. Due to the wood-anatomical intra-genus similarity of junipers54,55, and of deciduous oaks from the subgenus Quercus56, a definitive species-level identification was not possible. Based on the distribution of modern tree species in the region45,57,58, Dispilio oak wood samples most likely come from Quercus frainetto, Q. petraea, and/or Q. pubescens wood, and the junipers are most likely Juniperus excelsa, J. foetedissima, and/or J. deltoides (cf. J. oxycedrus).

The oak TRW chronology extends over 120 years and is composed of 58 wood samples (Fig. 4). It consists of tree-ring sequences with an average segment length of 66 years. Some sapwood was present on most of the oak samples (n=45); however, the final growth ring or “waney-edge”, which is important for archaeological interpretation, was conserved on only four pieces, as a result of either the lower durability of oak sapwood or its intentional removal. The mean inter-series correlation59 of the oak tree-ring sequences is 0.51.

A 303-years-long juniper TRW-chronology was also constructed with 118 tree-ring sequences and an average segment length of 86 years (Fig. 4). The mean inter-series correlation59 of the juniper chronology is 0.62. Juniper wood’s chemical60 and physical61 properties give it high resistance to degradation. These qualities made juniper wood the material of choice for construction purposes in many ancient societies in the Eastern Mediterranean62–64. The preservation of juniper wood in Dispilio is also exceptional and the waney edge on junipers is quite common, enabling an annually resolved reconstruction of the building phases and occupation duration on the site (Fig. 4b). All samples with a preserved waney edge had a final growth ring terminating with latewood, thus implying a felling date during the dormant period of the trees between late summer/autumn and early spring. The juniper and oak TRW chronologies have robust dendrochronological dating against each other (t-value=4.965 and =5.166; GLK=63%67) over a period of 108 years where sample replication is >4. This dendrochronological cross-dating between the two chronologies, considering that the oak chronology does not span the Miyake event, is independently supported by a conventional 14C wiggle-matching model of 11 14C measurements performed on tree-rings comprising the oak TRW chronology51 (Supplementary Note 1).

Tree-ring 14C cosmogenic signature and calendar-year dating
The preliminary modelled end-date range for the juniper tree-ring width chronology was established through a conventional radiocarbon wiggle-matching model68,69, with the IntCal2070 radiocarbon calibration curve (see Supplementary Note 1). On the basis of this coarse resolution wiggle-match dating we identified the wood samples and their corresponding tree-rings that should approximately span the period of the 5259 BC Miyake event. Four individual juniper wood samples were selected for annual 14C measurements, and the tree-rings approximately spanning the predicted position of the 5259 BC Miyake event were dissected at annual resolution (Fig. 3a and Supplementary Figs. 1-5). Here, we present the 115 single tree-ring 14C measurements (Supplementary Data 1) performed to locate the 5259 BC Miyake event in all four wood samples selected from the master Dispilio juniper tree-ring chronology (Fig. 3a). An average year-to-year increase (sensu Miayke et al.19) of ~15.8‰ in Δ14C was detected in all wood samples (Fig. 3a and Supplementary Data 1) in the exact same dendrochronologically cross-dated tree-rings corresponding to the relative year 184 of the Dispilio juniper chronology. This increase varies from the lowest of ~11.1‰ Δ14C in wood sample DISP-10070, to ~13.1‰ in DISP-10206, to ~14.8‰ in DISP-10063, and to ~18.6‰ in DISP-10611 (Fig. 3a and Supplementary Data 1).

To compare the 14C results from Dispilio with the published reference data for the 5259 BC event, a mean-value annually resolved reference curve (RC) was established from the dataset in Brehm et al. (2022: henceforth referred to as ‘BR22’22). A common approach to verifying the position of Miyake events is wiggle-matching using a goodness-of-fit χ2 test9,10,71 against a reference, so that the χ2 value becomes minimal for the correct placement of the sample’s waney-edge68. The lowest χ2 values are reached when the end-dates of the wood samples are placed at 5240 BC for DISP-10070 and DISP-10063 (Fig. 3b), 5153 BC for DISP-10206, and 5155 BC for DISP-10611 (Fig. 3c), corresponding to their cross-dated position along the tree-ring chronology. The 5259 BC event signal is clearly identified in all wood samples (Fig. 3a).

To test how close conventional radiocarbon wiggle-matching would be relative to the absolute calendar dating supplied by the Miyake event, the annual data from all four wood samples were wiggle-matched against the IntCal20 calibration curve70 using the OxCal 4.4 14C calibration software68,69. When IntCal20 is used, in none of the cases does the 95% probability end-date range include the actual felling date (Fig. 5 and Supplementary Data 3). Longer series of 14C dates that span some years before and after the event (Figs. 3a and 5), such as from wood samples DISP-10611 and DISP-10206, yield end-dates that are only ~15–20 cal years older, and shorter series, such as from wood samples DISP-10070 and DISP-10063, result in end-dates over ~40 cal years younger than the actual felling dates (Fig. 5). It has been noted previously72 that IntCal20 is poorly replicated during the 53rd and 52nd centuries BC. Notably, the 53rd century BC is represented by only 16 measurements, of which 14 are decadal and bidecadal blocks of 10–20 tree-rings, with only two 4-year and 5-year blocks70,73 (Supplementary Fig. 8). The variability in the calibrated end-date ranges suggests that IntCal20 might produce misleading results when wiggle-matching annual data coming from the period in question. The annual 14C dates were also wiggle-matched against a modified IntCal20, IntCal20plus, in which the default IntCal20 multiple-year blocks of before-present (BP) data for the 82-year period around the event were substituted with the average of the annual BR22 dataset. Calibrating against this dataset predictably yields the accurate and more precise end-date ranges at 95% probability for all wood samples (Fig. 5).

The growing season of trees is influenced by many factors and can vary between and within species as a function of cambial age, temperature, water availability, slope, aspect, soil type, and other factors. Personal observations of growth termination in modern oaks and junipers in the region have shown that latewood width at breast height can be completed in both genera by the beginning of September (Supplementary Figs. 6 and 7). While cell-wall thickening in temperate conifers continues for several weeks after the cessation of cell-wall enlargement74, the amount of cellulose carbon that would be deposited during this last stage of latewood formation constitutes a small percentage of the whole tree-ring75. Considering the robustness of the 14C signal in the Dispilio junipers tree-rings (Fig. 3) it is unlikely that it only represents the 14C incorporated at the end of the cell-wall thickening stage. Consequently, it can be inferred that the 14C signal of the 5259 BC event in the indeciduate junipers has been incorporated during the temperate growing season between spring and late summer/early autumn 5259 BC.

According to the dendrochronologically cross-dated position of all wood samples, the ring in which the Miyake event is detected corresponds to relative year number 184 of the 303-year-long juniper TRW chronology. This allows us to set the absolute end-date of the whole Dispilio juniper tree-ring chronology at 5140 BC. Furthermore, the identification of the event in wood samples DISP-10070 and DISP-10063 confirms the correct placement of the better-replicated earlier half of the chronology (Fig. 4a). Given the dendrochronological cross-dating between the juniper and oak chronologies, also the latter is absolutely dated, placing its last ring at 5311 BC (Fig. 4a.).

Site plan and felling phases
The timespan of 188 years between the earliest and latest felling dates (Fig. 4a) indicates the minimum duration of construction activities during Dispilio’s 54th–52nd centuries BC settlement phases. This timespan between 5328 and 5140 BC includes intermittent periods of wood felling and construction (Fig. 4a, b). However, the timespan between the earliest and latest felling dates in Dispilio need not alone reflect a continuous, uninterrupted occupation of the same location.

Wooden piles that have been dendrodated against the Dispilio juniper master chronology with felling dates within 1–2 years of one another, were plotted on the site plan using a GIS software (Fig. 4b). This revealed outlines that probably represent different structures (Fig. 4b). Identification of building outlines was possible only for groups that are composed of a substantial number of dendrodated samples. The structures seem to be oriented along the modern lakeshore; however, the shape of the Neolithic lakeshore is uncertain. Of note is the concentration of building activities in the eastern part of the Easte Sector (Fig. 4b). In this part, a group of wooden piles with a felling date of 5294 BC outline an area, superimposed by a group of piles with felling dates in 5258–5257 BC (Fig. 4a, b). The juniper group felled in 5294 BC is preceded by a potential felling phase ending in 5320 BC consisting of oak wood samples. However due to the poor preservation of oak sapwood only two of this group have preserved waney edge. These two securely dated piles are complemented by several other oak piles with final measured rings falling between 5328 BC and 5320 BC and no waney edge, but with at least 20 sapwood rings indicating the proximity of the waney edge. The mapping of the dendrochronological results also implies that building practices in some cases include either the short-term storage of timber for 1–2 years or a construction period spread over several years.

Methods
Wood samples
The wood material analysed in this study was sampled in August and September 2019 from wooden piles remains at the archaeological site of Dispilio, near Kastoria, Greece (40.485444 N, 21.289694 E; h=627 masl). The site is one of the best-known prehistoric sites in the country and has been investigated, almost continuously, since 1992. Excavations and sampling that took place on the site were performed in full compliance with the regulations of the Greek Ministry of Culture concerning archaeological material. The permit number for the wood samples obtained from the Ministry is: ΥΠΠΟΑ/ΓΔΑΠΚ/ΔΣΑΝΜ/ΤΕΕ/Φ77/379195/266411/4122/252, issued on 24.07.2020. During the 2019 fieldwork campaign, whole cross-section discs (n=787) were sampled from the wooden remains with handsaws and chainsaws. The wood samples’ documentation, cleaning, preparation, and sealing in plastic bags with water, took place on-site. Dendrochronological measurement began on-site and continued at the University of Bern. Tree-ring width (TRW) measurements were performed according to standard dendrochronological procedures99,100, with a measuring table under a binocular stereomicroscope. TRW were recorded with a precision of 0.01 mm. Two to four radii were measured per sample and averaged together to represent the sample. Descriptive dendrochronological statistics were performed in the dplR package in R59,101,102. The TRW measurements of DISP-10611, -10206, -10070, and -10063 are available in both Source Data and Supplementary Note 2. All wood specimens will be permanently deposited at the Dispilio Excavation Laboratory, Dispilio, Greece. Access is subject to obtaining permits from the Greek Ministry of Culture.

Wood taxonomy was determined from stem wood anatomy. Each measured wood sample was sectioned with a razor blade and cell arrangements in the transversal, radial, and tangential sections were identified and compared with references in wood-anatomical atlases55,56,103. Given the wood-anatomical similarity of various deciduous oak species from the subgenus Quercus56, and considering the high dendrofloristic diversity of oaks in the region57,58, it was not possible to distinguish them to species level. However, several deciduous oak species from the subgenus Quercus are likely to be represented, notably Q. frainetto, Q. petraea, and/or Q. pubescens. Oak trees from the subgenus Cerris are one of the more abundant groups of oaks in the region; however, no wood samples from Dispilio could be assigned to this group, which is anatomically characterised by larger and solitary latewood pores. Similarly, wood anatomical differentiation between different juniper species was not possible54,55,103. Considering today’s distribution of tree-like junipers in the region, the species most likely to have been used in Dispilio are Juniperus excelsa, J. foetedissima, and/or J. deltoides Adams (cf. J. oxycedrus). Although the majority of the pine samples exhibited denticulate walls on end-tracheids, a characteristic of the pine subgenus Pinus (cf. Pinus nigra/sylvestris-type), several pine wood samples could be identified as members of the subgenus Strobus (cf. P. peuce) by the presence of smooth-walled end-tracheids.

Modern local climatic conditions in the Kastoria Basin can be defined as continental to sub-Mediterranean, with temperate weather, continental winters, and warm and dry summers. The yearly average precipitation in the lower parts of ~700 mm increases with altitude. The wettest months are November and December, and the driest and hottest months are July and August. Yearly average temperature is ~12°C. Main climate classes according to the Köppen system104 are Cfa, Cfb, and Csa.

Sample preparation and radiocarbon measurement
Individual tree-rings were dissected by hand under a binocular microscope with a one-sided razor blade (Supplementary Fig. 5). Whole rings were used for all 14C measurements (Supplementary Data 1). About 30–70 mg of material was sampled per ring, depending on its width. Earlywood comprises ca. 80–90% of a juniper tree-ring. Because most of the of the ring-width of junipers growing on mesic sites is completed by the end of September105 (see also Supplementary Figs. 6 and 7), the tree-ring structural carbon concentration should reflect temperate spring-to-late summer carbon uptake.

Wiggle-matching of 11 14C dates from the juniper chronology (modelled end-date 5233-5137 cal BC, 95% probability, Supplementary Note 1) provided the basis for an initial estimate of the segment on the tree-ring chronology where the event was to be located. A series of 70 individual tree-rings centred around an estimated event ring were dissected from the first wood sample that was analysed (DISP-10206, Supplementary Fig. 1). The 14C content of every 4th sampled ring was subsequently measured until the 14C spike was identified, after which the 14C in 20 consecutive rings around the event was measured (Supplementary Data 1). The event ring on all the other wood samples (DISP-10611, DISP-10070, and DISP-10063, Supplementary Figs. 2-4) was identified according to the samples’ dendrodated position along the tree-ring chronology.

Cellulose from wood samples analysed at the Laboratory for the Analysis of Radiocarbon with AMS at the University of Bern (LARA)106 was extracted following the BABAB method107 including Sookdeo et al.’s.98 modifications at 70°C for all steps. Samples were submerged in a 1M NaOH overnight and treated in 1M HCl followed by 1M NaOH in a shaker for 1 h each. Bleaching of the samples was performed on addition of 5 mL water, a few drops of 1M HCl to reach pH 2–3 and 100 mg NaClO2 by shaking for at least 2 h or until the colour of the wood samples turned white. The material was dried by lyophilisation overnight. Samples were measured using the LARA MICADAS AMS system. In June–November 2022 the tree-rings from wood samples DISP-10070, -10206 and a first run of -10611 were analysed together with three oxalic acid II (SRM 4990C, NIST) standards and three chemical blanks. In June 2023, DISP-10063 and a second run of DISP-10611 were dated together with five oxalic acid II standards and four chemical blanks that were used for blank subtraction, standard normalisation, and correction for isotope fractionations. Two IAEA-C5, two IAEA-C7, two 1515CE reference samples and two cellulose blanks were also used as secondary standards and blanks, respectively. All initial results (Supplementary Data 1) were biased by an inappropriate batch of the oxalic acid II standard that was used for the measurements. A total of ten samples from our first run of DISP-10611 were repeated within our second run which gained an average negligible difference between both LARA runs of 0.6‰ so that our DISP-10611 dataset that is shown Fig. 3a represents the average of both LARA runs (Supplementary Data 2). By intercomparison with three other oxalic acid II batches (one of which was provided by ETH), an offset corresponding to a 14C age of +30.9 ± 3.2 years was determined for the inappropriate batch, whereas the results of the oxalic acid II of the other three batches were identical within uncertainties. The initial results were corrected for this offset yielding a shift of ~+4.2‰ for the samples. The corrected results are presented in Fig. 3a.

For the analyses performed at the Laboratory of Ion Beam Physics at ETH Zürich (ETH), the tree-ring samples were prepared in 15 ml glass test tubes together with four wood blanks (2 BC and 2 KB) and 2 1515CE reference samples each weighing 30–60 mg98,108. In a slightly modified procedure following107, samples were first soaked in 5 ml 1M NaOH overnight at 70°C in an oven. Then the samples were treated with 1M HCl and 1M NaOH for 1 h each at 70°C in a heat block, before they were bleached at a pH of 2–3 with 0.35 M NaClO2 at 70°C for 2 h. The remaining white holo-cellulose was then freeze-dried overnight. ~2.5 mg dried holo-cellulose was wrapped in cleaned Al capsules and converted to graphite using the AGE-3 automated graphitisation line. A measurement set was assembled comprising the tree-ring samples, three oxalic acid one (OX1) and four oxalic acid two (OX2) standards, two cellulose blanks, two chemical blanks, and two 1515CE reference samples and measured in the MICADAS accelerator mass spectrometer.

Radiocarbon matching and modelling
The 14C measurements presented in this study were matched to the constructed reference curve22 (Supplementary Data 3) using a common χ2 test approach (Eq. (1)) so that the χ2 value becomes minimal for the correct placement of the sample’s waney-edge9,10,68:

χ2(x) = Σn i=1 (Ri - C(x-ri))2 / (δRi2 + δC(x-ri)2)

where Ri ± δRi represents the 14C concentration in the tree-ring, C(x-ri) ± δC(x-ri) represents the reference 14C concentration in the curve, x is the assumed calendar year; and ri stands for the tree ring number starting with 0, representing the last growth ring of the tree (waney edge).

The Bayesian wiggle-matching was performed in the OxCal 4.4 software with the D_Sequence command against the atmospheric data from IntCal2069,70. For the CQL code see Supplementary Note 1, and the end of the .Rmd file in Supplementary Data 3.

The year-to-year increase in Δ14C presented in the Results section was calculated as a difference between the values in 5260 BC and 5259 BC (sensu Miyake et al.19). For a detailed discussion on the magnitude and 14C production during the 5259 BC Miyake event see 22 and 109. Calendar years are expressed according to the Gregorian calendar (AD/BC), without year 0.

Data uncertainty
The genus Juniperus is known to produce intra-annual density fluctuation (‘false rings’), and to have ‘missing rings’110 in parts of the stem. Missing rings are very often a product of the stem growth habit of junipers, termed ‘lobate growth’, which involves higher cambial activity and faster growth in certain areas of the stem, resulting in an undulating cross-section of the stem in older tress, where the less active areas may not produce rings in certain years. However, missing rings or measuring false rings can be accounted for when sufficient numbers of wood samples with complete stem cross-sections are available, as in Dispilio. The correct location of the “event ring” on all wood samples determined from their cross-dated position further supports an accurate ring count. Moreover, the dendrochronological cross-dating of the first half of the juniper chronology against the oak chronology provides an additional control for the correct ring count, because oak trees hardly ever have missing rings111.

Peer review rounds
[{"round": 1, "reviewer_comments": {"reviewer_1": "This study at Dispilio revealed robust oak and juniper tree-ring chronologies, providing a 120-year oak TRW chronology and a 303-year juniper TRW chronology. The detection of the 5259 BC Miyake event in the juniper chronology allowed for the absolute dating of both chronologies, placing the end-dates at 5140 BC and 5311 BC, respectively. Additionally, the findings suggested a 188-year minimum duration of construction activities at the site, with intermittent building phases and occupation durations. This study contributes to understanding the transitional period in the Neolithic era, highlighting changes in settlement dynamics, societal focus, and human impact on the local environment during the late 6th millennium BC. Furthermore, it underscores the significance of high-resolution chronological data in unraveling the complex interplay between humans and their surroundings, particularly in the context of climate influences on past societies.\nThis research has a significant impact in the fields of archaeology, dendrochronology, and climate science by offering an absolute dating framework for the Dispilio site, shedding light on its construction phases and offering valuable information usefull to infer environmental conditions and human adaptations during the studied time frame. This work distinguishes itself from existing literature through its meticulous integration of dendrochronological, radiocarbon, and archaeological analyses, providing a nuanced understanding of societal changes, human-land interactions, and the regional environment during the later Middle Neolithic and Late Neolithic periods.\nThe work robustly supports the conclusions and claims made, providing detailed and meticulously analyzed data from dendrochronological and radiocarbon studies. The interdisciplinary approach enhances the reliability of the findings, reinforcing the chronological framework and the construction phases of the Dispilio site. The comprehensive analysis of wood samples, combined with high-resolution radiocarbon dating, bolsters the credibility of the interpretations about settlement duration and the societal changes during the Neolithic period.\nWhile the data analysis and interpretation are clear and robust, some limitations can be identified, including the inability to definitively identify certain species due to anatomical similarities or the challenges in precisely determining the dating of certain building phases. These factors have been in any case well addressed in the discussion and suficiently justified as elements that have no crucial impact on the conclusions of this research and that are open for further investigation in the future.\nThe methodology employed in this study appears to be rigorous and adheres to the expected standards in the field. Proper sampling and documentation protocols were followed, and tree-ring measurements were conducted using established dendrochronological procedures. The wood taxonomy determination was performed carefully, and the radiocarbon measurements were conducted using a detailed and well-documented approach. Overall, the methodology seems sound and in line with the standard practices of the field.\nAt the same time materials and methods section appears to provide sufficient detail for the work to be reproduced. Detailed descriptions of the wood sampling process, preparation procedures, and dendrochronological measurements were included. The methodology for radiocarbon measurement and matching was also thoroughly outlined, along with specific details regarding the sample preparation and analytical techniques used. Therefore, researchers in the field should have the necessary information to replicate the study and verify its results.\nI thoroughly enjoyed reading this well-accomplished research. I recommend sending the manuscript to an English language reviser to correct any writing mistakes, which I am unable to identify as a non-native English speaker. Additionally, I suggest double-checking the text for typos, as a repeated phrase was noticed in line 363. After addressing these minor corrections, I am delighted to recommend this paper for publication.", "reviewer_2": "The manuscript ‘Absolutely dating the European Neolithic through a rapid 14C excursion’ presents new and exiting results from the intersection between archaeology, 14C dating and dendrochronology, with significant relevance for a wider range of fields. The material, methods and results are suitably presented and meet current standards within the fields, at times even exceeding it and creating higher standards for future studies. The results are discussed within a larger framework and in support of the conclusions. With some minor revisions, I find the manuscript well-suited for publication in Nature Communications.\nUnderneath I include a list of minor points whereupon the manuscript may be further improved.\nOverall, the language is ok, but could be improved in several places.\n• Line 28-30: “Dispilio is thus the first prehistoric site absolutely dated through a 14C signature (Miyake event), but also the first absolutely, calendar-year dated prehistoric site in the wider Mediterranean region”.\ni) This depends on the definition of ‘prehistory’, which is highly regionally dependent. I recommend referencing other studies that have identified Miyake events in archaeological materials, e.g., Kuitems, M., Wallace, B. L., Lindsay, C., Scifo, A., Doeve, P., Jenkins, K., Lindauer, S., Erdil, P., Ledger, P. M., Forbes, V., Vermeeren, C., Friedrich, R., & Dee, M. W. (2022). Evidence for European presence in the Americas in ad 1021. Nature, 601(7893), 388-391. https://doi.org/10.1038/s41586-021-03972-8\nMeadows, J., Zunde, M., Lēģere, L., Dee, M. W., & Hamann, C. (2023). SINGLE-YEAR 14C DATING OF THE LAKE-FORTRESS AT ĀRAIŠI, LATVIA. Radiocarbon, 1-11. https://doi.org/10.1017/RDC.2023.24\nPhilippsen, B., Feveile, C., Olsen, J., & Sindbæk, S. M. (2022). Single-year radiocarbon dating anchors Viking Age trade cycles in time. Nature (London), 601(7893), 392-396. https://doi.org/10.1038/s41586-021-04240-5\nii) The latter part of the sentence gives the impression that Dispilio is the only prehistoric site that has been absolutely dated, I assume ‘absolutely dated to a single-year calendar’ is what is meant.\n• Introduction: The introduction could benefit from being more archaeologically focussed to better present the context for the scientific results. The relevance of Dispilio in relation to the Mesolithic-Neolithic transition in this region is lacking, which renders the introduction of little relevance to the remaining manuscript. I suggest Shennan (2018) might be of relevance here:\nShennan, S. (2018). The First Farmers of Europe: An Evolutionary Perspective. Cambridge University Press. https://doi.org/10.1017/9781108386029\n• Line 51: “Until now” gives the false impression this is the first study to apply a combined approach of dendrochronology and 14C dating of Miyake events. Please provide references to earlier applications.\n• Line 73: Logically the Mesolithic should be mentioned before the Neolithic.\n• Line 89: What qualifies Dispilio as a ‘premier prehistoric wetland site’? I miss a definition of the type, was it a settlement/fortified site/burial site/etc? Also, was it a commonly occurring type of site for this period and region?\n• Line 100: I find it confusing that the text refers to 1700 complete ceramic vessels, but Fig 2 illustrates a fragmented vessel.\n• Line 101-02: Using the term network invokes notions of trading and contacts, at least in the minds of archaeologists, but I suspect the authors refer to artefact typology here.\n• Line 105-06: I suggest describing these as ‘floating chronologies’.\n• Line 110: see earlier comment on line 28-30.\n• Line 130: Fig 4 is introduced before Fig 3.\n• Figure 4: Please state clearly what methods were used to anchor the floating tree-ring-series chronologically, i.e. was it the “conventional radiocarbon wiggle-matching models” (line 149), or perhaps the use of the Miyake event?\n• Line 147, Supplementary S1: provides a wiggle match model of oak block ID Disp-6001, but 1) the purpose of the model is unclear, and 2) block Disp-6011 and related 14C dates are neither described nor included elsewhere in the manuscript or supplementary material.\n• Line 149ff: I find it confusing throughout the paper what wooden block were analysed, their species, ID, number of tree rings and which rings that have been 14C dated. I suggest inserting a table with the information. This might also clarify how you can wiggle match “blocks of 1-11 tree-rings”?\n• Figure 3: The box in the topmost right corner of figure 3a is not described in the figure text.\n• Line 223: Please briefly state what is meant here by the term ‘cross dated’, i.e. dendrodated wooden objects that has been cross dated to the absolutely dated master curve.\n• Line 244: How can the timeframe be ‘universal’ if it is regional?\n• Line 246: Please state what makes “the absolute dating and duration” unique. The precision? Is the duration particularly short/long?\n• Line 290: Why are these other sites described as ‘peripheral’? In relation to their regional significance or simply due to their geographical position in relation to Dispilio?\n• Line 291: See earlier comment about the use of the term ‘network’, I assume the authors refer to ‘chronological framework’.\n• Line 310: Annual radiocarbon measurements (missing word.\n• Line 311: Improving the resolution of the radiocarbon calibration curve, thereby improving the precision of the calibrations.\n• Line 354-58: Please state that this is based on modern data.", "reviewer_3": "The paper is interesting and the approach is new. However, I think that the introduction should be re-written, some of the references updated and others changed. There is quite a bit of confusion regarding the Mediterranean or Balkan location of the site that should be clarified. The archaeological cultural aspect of the site is never mentioned. This should be added somewhere. In my opinion the chronological method employed is interesting and innovative. But one of the points regards also the settlement duration period. There are many points to be clarified and revised. This is my general impression"}, "author_response": "# We would like to thank Reviewer #1 for the thorough review and recommendation! The\nmanuscript has been revised by a native English speaker who is a professional in scientific\nwriting.\nAlso, the mistake on line 363 was corrected accordingly\n\n# We would like to thank Reviewer #2 for the very thorough and kind review!\nThe suggested changes were fully incorporated, and the abstract was clarified accordingly by\nspecifying that what is meant is European prehistory and calendar-year absolute dating.\n\n# At the beginning of the introduction, we provide a brief, general temporal and\nphenomenological setting of the Neolithic as it is defined in western Eurasia. We clarified the\nspatial framework within which this study is set. The paragraphs that follow provide a\ncomprehensive overview of the methodology combining dendrochronological, archaeological,\nand 14C information. Further, the reader is introduced to wetland archaeological sites that are\nexceptionally significant in prehistoric archaeology considering the often-unique preservation of\norganic material, including wood. Lastly, detailed information is provided on the setting of the\nsite of Dispilio, its chronology, regional significance, and wooden artifacts. We clarified\npotentially misleading parts, as the article does not deal with the Mesolithic–Neolithic transition,\nwhich would have occurred over a millennium before the absolutely dated phases at Dispilio. The\nMeso-Neolithic transition itself is a topic with very little evidence considering the scarcity of\nMesolithic sites in the Balkans.\n\n# This was clarified by using instead the expression “until recently”, as the use of Miyake\nevents for dating historical or archaeological sites was first used only in 2014 (Wacker et al.,\n2014, reference added), and since then only about a dozen studies have appeared using Miyake\nevents. We also adressed this by expanding references to other studies who have conducted this\nsort of work.\n\n# Corrected.\n\n# We clarified this. Dispilio’s importance lies in the fact that it is the only wetland settlement or\n‘pile-dwelling’ in the Balkans to be systematically excavated over multiple years and on a large\narea.\n\n# Sentence clarified. Under “complete” in European Neolithic sites, one can include vessels\nfrom which most parts are preserved in such a manner that even the missing pieces can be\nreconstructed with great certainty. For instance, intentional, perhaps ritual, vessel breaking is a\ncommon feature observed in various sites during the Neolithic in Southeastern Europe, a practice\nwhich leads to the formation of sites with great amounts of pottery that do not have any intact\n“complete” vessels, but have many vessels whose parts are all preserved in the layer. Dispilio is\ncharacterised by its large collection of both in situ complete and also fully restored vessels. The\nvessel in Figure 2, considering its bilateral symmetry, is one such vessel for which all parts\nnecessary for full restoration have been preserved, but the full restoration has not yet taken place,\nso only the original parts are visible. Nevertheless, the reference to this figure is removed to avoid\nunintentional confusion. We thank the reviewer for raising this.\n\n# Thank you for this observation, we clarified that what is referred to as ‘network’ is a ceramics\ntypology network.\n\n# It is clarified that we refer to floating tree-ring width chronologies. The oak and juniper tree-ring\nchronologies are then described in detail in the Results section of the article and are now\nabsolutely dated.\n\n# Thank you for the suggestion, definition clarified.\n\n# Corrected.\n\n# Figure 4 caption clarified and expanded as suggested.\n\n# The wiggle-matching model of the oak chronology is now better defined. 6001 is the ID of the\noak chronology. All radiocarbon dates used in the model are included in the OxCal CQL code in\nthe Supplementary Material S1. Table S1.3 in Supplementary Material S1 was added: it lists and\ndescribes all the radiocarbon dates included in the wiggle-matching model of the oak chronology.\nThe wiggle-matching of radiocarbon dates from the oak chronology is supporting the\ndendrochronological cross-dating between the oak and juniper tree-ring chronologies.\n\nWe agree that “blocks of 1-11 tree-rings” was confusing and have removed this from the text. We\nhave also tried to clarify the associated text which may have added to the confusion. The\nexcavation IDs of the wood samples that were sampled for annual 14C measurements are DISP-\n10063, DISP-10070, DISP-10206 and DISP-10611. All four wooden samples, cross-sections cut\nfrom vertical wooden piles, are described in the Results section of the main article text, and\nschematically represented in Figure 4, while the photographs of each wood sample are available\nin Supplementary Material S2. In response to the table suggestion, we actually had\nSupplementary Table T1 already, which contains some of the relevant information (wood\nsamples’ IDs, rings sampled and corresponding radiocarbon measurements, archaeological site\nlocation, 14C lab at which the measurements were performed) but we have added information on\nthe total ring number of each sample. Total ring number and ring-widths measurements were also\nprovided in Supplementary Material S3.3. All juniper 14C measurements discussed in the main\narticle text are annual, i.e. performed on single tree-rings as listed in Supplementary Table T1.\nHowever, initially, in order to place the juniper chronology on an absolute time frame, so even\nbefore the publication of the Brehm et al.’s (2022) findings, 11 radiocarbon measurement were\ntaken from the juniper chronology to understand its approximate placement on the calendar\nscale (we now added also these initial juniper radiocarbon measurements to Sup. Mat S1). These\ninitial results were the guide for the identification of the area of the juniper chronology where the\nMiyake event would be located.\nThe juniper and oak tree-ring chronologies cross-date dendrochronologically against each other,\nwith an overlap over 108 years, placing the last ring of the oak chronology at 5311 BC, i.e. before\nthe 5259 BC Miyake event. This dendrochronological cross-dating between the two chronologies\nis also supported by a wiggle-matching model of 14C measurements obtained from blocks of\nseveral tree-rings from oak wood samples that make up the oak chronology, and the median ring\nof each block of tree-rings was used in defining the gaps in the wiggle-matching model of the oak\nchronology, as described in the updated Supplementary Material S1 Table S1.1. The oak wiggle-\nmatching model results have been described in an earlier article in an edited volume (Prehistoric\nWetland Sites of Southern Europe: Archaeology, Dendrochronology, Palaeoecology and\nBioarchaeology), originally scheduled for publication in 2022, which is already typeset and should\nbe published anytime now (main article ref. Maczkowski et al., 2024).\n\n# Yes, we overlooked describing the inset in panel a. Now corrected, rest of Figure 3 caption has\nalso been expanded and clarified, thank you!\n\n# Paragraph updated accordingly.\n\n# What is meant is an “unanimously agreed upon absolute timeframe”. Sentence clarified.\n\n# Yes, it is the precision that makes the absolute dating unique. We further clarified in the\nparagraph that all estimates of house and settlement occupation durations in south-eastern\nEurope are based solely on 14C modelling, which has an associated uncertainty that at times can\nbe of several decades, so longer than a generation. Additionally, the geographically closest\naccurate radiocarbon models of house and settlement durations come from sites in northern\nSerbia and Hungary, and detailed radiocarbon dating programs focusing on Neolithic settlement\ndurations further south in the rest of the Balkans, but also Anatolia, do not exist.\n\n# Thank you for this remark, the chosen term is indeed inappropriate. What are meant are the\n‘neighbouring’ sites surrounding Dispilio within a relatively short distance, in dendrochronological\nterms, of ca. 90 km.\n\n# Thank you for this remark, the sentence has been clarified. Yes, we refer to the\n“dendrochronological network”, a term commonly used in dendrochronology, i.e. “tree-ring\nnetwork”, a term that denotes a geographical network of different tree-ring chronologies which\nhave high correlation values between them, indicating a common regional or synoptic scale\nclimatic signal preserved in the tree-rings (see: ucar.edu). In this sense, the three-centuries long\nDispilio juniper chronology can be extended through cross-dating with other wood samples or\nchronologies from the neighbouring Neolithic sites.\n\n# Missing word inserted, thank you.\n\n# Sentence clarified accordingly, thank you.\n\n# Clarified that what are described are the modern climatic conditions.\n\n# We would like to thank Reviewer #3 for the kind review! The comments of Reviewer #3 were\nincorporated in the PDF version of the manuscript, so they are copied and pasted here and\nanswered accordingly.\n\n# Thank you for the remark! We acknowledge that this might be confusing to the reader. We\nadapted the sentence accordingly, removing the reference to the Levant.\n\n# Thank you; the suggested references were included. Also, it is stated in the first paragraph of\nthe introduction that the appearance of the Neolithic occurs at approximately at similar times in\nthe Aegean and Northern Greece.\n\n# We absolutely agree, there is very little information on the Mesolithic-Neolithic transition in the\nregion given the scarcity of sites which document both periods, as represented only by Franchthi\nCave and Cyclops Cave. However, regardless of the archaeological information and material\nculture, changing land use practices can be inferred form pollen spectra, tree-rings, and other\nnatural proxies.\n\n# Thank you for the remark. We defined the type of site accordingly. Yes, the site is located in the\nGreek administrative unit of Western Macedonia, which is bordered to the east by the\nadministrative unit of Central Macedonia, to the north by the country of North Macedonia, to the\nwest by the country of Albania and the Greek administrative unit of Epirus. Given the broader\naudience at which the journal Nature Communications is aimed at, we use more general\ngeographical terms that are more familiar to a broader audience, rather than terms that include\nlocal administrative divisions. The precise location of the site is also illustrated on Figure 1,\npanels a. and b.\n\n# It is clarified that the site is situated in northwestern Greece, and its significance is defined as\nthe only systematically excavated pile-dwelling in the Balkans is defined.\n\n# The coastal and inland areas of many parts of the Balkans are often defined as “mediterranean”\nby different sources. Both the definition of “Balkans” and “Mediterranean” are often ambiguous\nas they can have different meanings depending on what is the basis of the definition, whether it is\npolitical borders, geography, culture, vegetation, climate, proximity to the sea, etc. This paragraph\ndiscuses tree-ring chronologies constructed for the wider Eastern Mediterranean region, given\nthat the climate signal preserved in tree-rings is often common for trees on a regional and\nsynoptic scale, i.e. up to 1000 km away and even more. The vegetation in northwestern Greece\nand in the neighbouring areas of Albania and North Macedonia contain plant communities\ncharacteristic of the Mediterranean, and the summer climate is also most often described as\nsub-Mediterranean. The contacts with the sea of these part of the Balkans, and even further\nnorth, have been constant since at least the Neolithic (e.g. spondylus shell bracelets in Dispilio)\nuntil today. We further clarify this paragraph by specifying that what is meant is absolute\ncalendar-year dating as, to our knowledge, there is no other Neolithic site in the whole\nMediterranean basin that has been absolutely dated to single-alendar-year precision.\n\n# Thank you for this remark. We acknowledge that it was not entirely clear what was meant. The\nparagraph was clarified to explain that plotting of wooden piles that have been dendrodated and\nhave the last ring in the same year revealed blueprints of buildings as shown in Figure 4b.\n\n# The sentences were rewritten, and a reference was added to clarify this part. The defining\ncharacters and the timing of the transition from Middle to Late Neolithic in the region has not\nbeen agreed upon in an absolute timeframe. Furthermore, the terminology has not been agreed\nupon even across borders, so for instance the 54th–52nd centuries BC in Albania would fall in the\nMiddle Neolithic, in Aegean terminology it is the Late Neolithic I, and in the more general Balkan\nterminology this would fall at the transition between the two. For some, the latter part of the 6th\nmillennium might even be attributed even to the early Chalcolithic. The division of Early, Middle,\nand Late Neolithic was established by Weinberg, and has been in place since 1942. Such a\ndivision was very useful and meaningful when radiocarbon was not available, and the excavated\nsites were few. However, with the great number of excavated sites and more detailed excavation\ntechniques during the course of the 20th and 21st centuries produced a much more diverse and\nnuanced picture of the changes occurring in the archaeological record. However, some\ngeneralisations are possible, for instance concerning the pottery decoration, switching from\nwhite-on-red to darker pottery with incised decoration in the Late Neolithic. Sites’ locations also\nchange, and the Late Neolithic ones are spread in all environments, while population densities\nincrease, and changes in burial customs are documented. These changes vary between both\nregions and sites. The definition of the Middle and Late Neolithic is outside the scope of our\npaper. The absolute dating of Dispilio is in fact a step forward towards dealing with the at times\nconfusing concepts associated with the tripartite periodisation of the Neolithic and their\ncorrespondence on wider geographical scales.\n\n# Thank you for this remark. As discussed above in the reply to Line 110, the terms ‘Balkan’ and\n‘Mediterranean’ are often ambiguous and depend on the definition and the context. The southern\nparts of the Balkans, especially when considered in terms of vegetation, but also cultural\ncontacts, are part of the wider Mediterranean.\n\n# The duration of occupation of Neolithic settlements and individual dwellings in Southeastern\nEurope has been so far estimated only through radiocarbon modelling. And while the radiocarbon\nmodels can provide satisfactory resolution at times, this is only possible on sites that have been\nexcavated on a sufficiently large area with modern, detailed excavation techniques where a great\nnumber of radiocarbon dates are available, as in the examples presented by Tasic et al., 2016 and\nBayliss and Whittle, 2018. However, such techniques are limited by the associated uncertainty of\nradiocarbon measurements, the replication, and the shape of the radiocarbon calibration curve.\nMoreover, radiocarbon dates on wood charcoal are susceptible to the so-called ‘old wood effect’,\nby which the radiocarbon-dated charcoal might come from the inner part of an old tree, which\ncan yield dates that are too old by up to a century or more. Consequently, the replicated\ndendrochronological information from Dispilio provides the duration of the settlement phases\nand the duration of buildings in calendar years, independently of radiocarbon.\n\n# Yes, this refers to the period for which we have secure felling-dates: wood samples with the\npreserved final ring (or bark). From the earliest secure felling-date to the latest, as identified\nsolely from the dendrodated wood samples in the East Sector, there are at least 188 years. The\nphrase “at least” indicates that we do not know whether some of the undatable wooden piles\ncome from later or earlier than this, or whether other areas of the site preserve piles that\ndocument felling dates outside the 188-years range.\n\n# We fully recognise the limitations of archaeological data, as archaeological sites are products\nof very complex, stochastic formation processes. Because we cannot determine what is missing\nfrom the archaeological record, interpretations must be made with caution, and, as in the given\nparagraph, several interpretation options should be listed as starting hypotheses for a future re-\nevaluation.\n\n# Thank you for this comment, we presume that it concerns the models depicted in Figure 5. The\ndata is available in the Supplementary Material 4\n\n# The changes observed at the end of the 6th millennium BC include rising population numbers,\nand an associated increase in the number of settlements. As cited references describe, there are\nchanges in architecture and settlement organisation, in pottery decoration, and the first proxy\nindication of environmental changes most probably induced by anthropic activity.\n\n# Periods clarified as suggested.\n\n# Yes, this phenomenon is attested in other regions as well, as the Neolithic sedentary farming\nsocieties would have chosen locations within reach of water sources."}, {"round": 2, "reviewer_comments": {"reviewer_2": "The authors have revised the manuscript in a satisfying manner, and I am content with the result. The only thing I object to that there are no references to previous studies identifying single years in archaeological material, despite my previous suggestion (see extract of my previous comments below). The text now reads: \"Dispilio is thus the first European prehistoric Neolithic site dated absolutely dated to a calendar year through a 14 35 C- signature (Miyake event)\", which is not wrong, but it does give the implicit message that this is also the first study to date an archaeological site to a single calendar year - which it is not. I strongly recommend referencing and acknowledging previous publications applying comparable methodologies. This will not remove the importance and impact of the present study.\n• Line 28-30: “Dispilio is thus the first prehistoric site absolutely dated through a 14C signature (Miyake event), but also the first absolutely, calendar-year dated prehistoric site in the wider Mediterranean region”.\nReviewer 2: This depends on the definion of ‘prehistory’, which is highly regionally dependent. I recommend referencing other studies that have idenfied Miyake events in archaeological materials, e.g.,\nKuitems, M., Wallace, B. L., Lindsay, C., Scifo, A., Doeve, P., Jenkins, K., Lindauer, S., Erdil, P., Ledger, P. M., Forbes, V., Vermeeren, C., Friedrich, R., & Dee, M. W. (2022). Evidence for European presence in the Americas in ad 1021. Nature, 601(7893), 388-391. htps://doi.org/10.1038/s41586-021-03972-8\nMeadows, J., Zunde, M., Lēģere, L., Dee, M. W., & Hamann, C. (2023). SINGLE-YEAR 14C DATING OF THE LAKE-FORTRESS AT ĀRAIŠI, LATVIA. Radiocarbon, 1-11. htps://doi.org/10.1017/RDC.2023.24\nPhilippsen, B., Feveile, C., Olsen, J., & Sindbæk, S. M. (2022). Single-year radiocarbon dang anchors Viking Age trade cycles in me. Nature (London), 601(7893), 392-396. htps://doi.org/10.1038/s41586-021-04240-5", "reviewer_3": "The paper has been accurately revised. I have only three more recommendaons which may be useful\nYou use somemes northern Greece, somemes northwestern Greece. Maybe beter to unify the terminology (northwestern??)\nLine 26. Perhaps beter Aegean and Balkan.... add also Balkan\nLine 53. Would be more correct to add the reference Biagi, Shennan, Spataro... Rapid rivers and slow seas that was the first to address the problem. Easy to find on the internet"}, "author_response": "# We would again like to thank Reviewer #2 for the very thorough and helpful review in the first and\nsecond round! References to Wacker et al. 2014 and Kuitmes et al, 2022 were originally included in the\nmanuscript. We added the other two references suggested by the reviewer (Meadows et al., 2023 and\nPhilippsen et al., 2022).\n\n# We would also like to thank Reviewer #3 for the review and helpful comments! We adapted the\nterminology, accordingly, going from the broader ‘Northern Greece’ to the narrower ‘Northwestern’ as\nwe go from broader regional seng to the more specific context of the site within the text.\n\n# Suggeson added.\n\n# We could not idenfy the line for which this reference was suggested. Addionally, the relevance of\nthe suggested reference “New Observaons on the Radiocarbon Chronology of the Starcevo-Cris and\nKoros Cultures; Rapid Rivers….” by Biagi et al., 2005 is limited to the subject of our study, considering\nthat Biagi et al. focus on the Early Neolithic in Romania, Hungary and Northern Serbia."}]

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