# Geochronology/Middle Ages

The Middle Ages is usually regarded as a period of European history from the fall of the Roman Empire in the West (5th century) to the fall of Constantinople (1453), or, more narrowly, from c. 1100 to 1453.
The apparent Dark Ages lasted from the destruction of the Western Roman Empire until about 500 b2k, or it's the period in western Europe between the fall of the Roman Empire and the high Middle Ages, c. ad 500–1100, during which Germanic tribes swept through Europe and North Africa, often attacking and destroying towns and settlements.
"The latest Roman levels are sealed by deposits of dark coloured loam, commonly called the 'dark earth' (formerly 'black earth'). In the London area the 'dark earth' generally appears as a dark grey, rather silty loam with various inclusions, especially building material. The deposit is usually without stratification and homogeneous in appearance, It can be one meter or more in thickness. [...] The evidence suggests that truncation of late Roman stratification is linked to the process of 'dark earth' formation."
"The sediments in the Thingvellir lake basin have been successfully dated by tephra layers back to ca. AD 900, the time of Nordic Settlement in Iceland."
"Contemporary literature refers directly to tephra fall in the Thingvellir area during the following eruptions [see the X-ray radiographs of the cores on the left]: Katla 1918, 13 October (Sveinsson 1919); Hekla 1766-68, 16 July 1766 (Thörarinsson 1967); Katla 1721, most likely 13 May (Thörarinsson 1955). Tephra fall in adjacent regions is mentioned during the following eruptions: Vatnajokull 1766, 24 July (Thörarinsson 1974); Hekla 1693, sometime between mid February and the end of July (Thörarinsson 1967); Hekla 1510, 25 July or later that summer (Thörarinsson 1967); Hekla 1341, 19 May or later that summer (Thörarinsson 1967)".
"Tephra layers from three historical eruptions, not mentioned in written sources, have been traced into the Thingvellir area, i.e. Katla - 1500, Katla-R from the early 10th century and Vatnaoldur - 900, also named The Settlement Layer (Thörarinsson 1959, 1967, Larsen 1978, 1984a). Neither the year nor the season of deposition are accurately known. In addition, a tephra layer from a subaqueous eruption near Reykjanes in the 13th or 14th century, the Medieval tephra layer, has been traced into the region west of the lake (Olafsson 1983), and the tephra layer from the Eldgjd eruption AD 934 ± 2 has been traced into the region east of the lake."

## Theoretical Middle Ages

Def. the "period of primarily European history between the decline of the Western Roman Empire (antiquity) and the early modern period or the Renaissance; the time between c. 500 and 1500" is called the Middle Ages.
Def. the history of "or relating to the Middle Ages, the period from about 500 to about 1500" is called medieval history.

## Short History of Middle Ages

| Months (Roman) | Lengths before 45 BC | Lengths as of 45 BC | Months (English) |
| Ianuarius | 29 | 31 | January |
| Februarius | 28 (in common years) In intercalary years: 23 if Intercalaris is variable 23/24 if Intercalaris is fixed | 28 (leap years: 29) | February |
| Mercedonius/Intercalaris | 0 (leap years: variable (27/28 days) or fixed) | Abolished | — |
| Martius | 31 | 31 | March |
| Aprilis | 29 | 30 | April |
| Maius | 31 | 31 | May |
| Iunius | 29 | 30 | June |
| Quintilis (Iulius) | 31 | 31 | July |
| Sextilis (Augustus) | 29 | 31 | August |
| September (Roman month) | 29 | 30 | September |
| October (Roman month) | 31 | 31 | October |
| November (Roman month) | 29 | 30 | November |
| December (Roman month) | 29 | 31 | December |
Dates are correct for the Julian calendar, which was used in Russia until 1918. It was twelve days behind the Gregorian calendar during the 19th century and thirteen days behind it during the 20th century.

## Late Middle Ages

The Late Middle Ages extends from about 700 b2k to 500 b2k.

## 15th century

"Italy from the peace of Lodi to the first French invasion (1454-94): the era of equilibrium" is near the end of the late Middle Ages.
On the right is an image of an incense burner from the Tarascan culture, showing a deity with a "Tlaloc headdress", 1350 - 1521 AD, from the Snite Museum of Art.
The image second down on the right hangs in the interior of the ayuntamiento of San Cristobal de La Laguna, Tenerife.
The painting on the right shows the surrender of the Guanches kings of Tenerife to Ferdinand and Isabella. This appears to have occurred c. 504 b2k.
The painting on the left was painted in 1764. It depicts the surrender of the Guanches leaders Bencomo mencey with Tacoronte, Anaga and Tegueste to Governor Alonso Fernández de Lugo with his captains and noble friends, by bringing gifts to the governor.

## 14th century

Italian humanism began in the first century of the late Middle Ages (c.1350-1450).
"The processed image at the right [in the images on the right] is the product of the application of digital filters. Digital filters are mathematical functions that do not add any information to the image, but transform it in such a way that information already present in it becomes more visible or easier to appreciate by the naked eye. The processed image was produced by inverting the brightness of the pixels in the positive image but without inverting their hue, and then by increasing both the brightness contrast and the hue saturation. Finally noise and so-called “salt and pepper” filters automatically removed the noisy information from the original image which hinders the appreciation of the actual face. To my knowledge the resulting image is the best available and indeed the only one that reveals the color information hidden in the original."

## 13th century

"The town of Tzintzuntzan, in addition to being a Pueblo Magico, is the heartland of Michoacan’s indigenous culture as it once served as the ceremonial center and capital of the Purépecha empire (Tarascan). The ceremonial center now is an outstanding archaeological site that contains five temples, called yacatas, which date back to the 13th century. Tzintzuntzan’s indigenous customs, traditions, and language are still very much present today."

## High Middle Ages

The High Middle Ages date from around 1,000 b2k to 700 b2k.
"The first large-scale dike building activities commenced during the High Middle Ages, from the 11th to the 13th century. This marked a significant change in the relationship between man and nature. Whereas previously the sea flowed freely over the whole region during storm tides, it was now shut out. This provided an enormous boost to habitation and agriculture but when storm surges broke through dykes, people and cattle drowned in high numbers. These disasters were perceived as God’s aversion towards human wealth and corruption of moral standards, and had a lasting imprint on the mentality of the coastal population (Jakubowski-Tiessen, 2011)."
"Next to the building of dykes, the large-scale exploitation of the extensive peat lands between the clay areas and the sandy areas in the High Middle Ages also had a major impact on the coastal environment. In terms of water management, the construction of dykes and the exploitation of the peatlands cannot be considered separately (De Jonge, 2009). The exploitation together with the oxidising of the peat caused lowering of the level of the mainland behind the dykes which became a permanent challenge for drainage. Salt and peat mining also substantially contributed to the lowering of the marsh surface below the level of the sea."

## Early Middle Ages

The Early Middle Ages date from around 1,700 to 1,000 b2k.
There "appears to be evidence for a major outbreak of [Yersinia pestis]-plague peaking at the end of the “733–960 AD”$^4$ time span."
"In [Great Moravia] some 30 major fortresses, at least nine of them with stone churches, are utterly devastated: "The most recent burnt horizons give evidence for a gigantic annihilation that is roughly datable to the time of 900 CE“$^{11}$. More recently, the demise of the Great Moravia Empire is dated into the early part of the 10th century"$^{12}$."
"Salzburg, [Austria]’s most important Early Medieval center, becomes “multiple times smaller”$^{13}$ after a devastation in the 10th century when it resorts to primitive wooden houses for the few survivors.$^{14}$"
"In [Hungary], the Early Medieval town of Mosaburg with its strikingly Roman style stone Basilica of Zalavár-Récéskút (9th/10th c.) “had become ruinous by the Arpadian age. / Dateable finds from the multilayer cemetery could all be dated to the years from the second third or middle of the 9th century to the early 10th century, namely to its first few decades. / / Not just Mosaburg/Zalavár became depopulated, but also its surrounding area“$^{19}$."
"Egypt’s most famous export item, writing material made of sheets of papyrus (Cyperus papyrus or Nile grass) ceased to be cultivated around the 10th c. CE$^{43}$: “All in all, we can say that after the 11th century no writing materials were produced from the papyrus plant"$^{44}$. The plant had been virtually wiped out".
At left is an attempt to correlate the change in $^{14}$C with time before 1950. The different data sets are shown with different colored third order polynomial fits to each data set.
"The Δ$^{14}$C values in a chronology can clearly be used to identify catastrophic gaps and catastrophic rises in carbon-14."
The first four gaps have a jump up in $^{14}$C with a fairly quick return to the calibration curve shown in the figure on the second left. However, from about 2000 b2k there is a steady rise in the Δ$^{14}$C values.
Zea mays from the Lake Pátzcuaro Basin, Mexico, was radiocarbon dated at 900-1,000 AD (1010 b2k intercept).
"After the sword [center image] was found we have made two surveys, we found a fibula from the period 300-400 A.D."

## Hypotheses

* Each century from 3000 to 500 b2k has been demonstrated to exist by radiocarbon dating or dendrochronology of an artifact.