## 1 Introduction
### Study Area and Archaeological Background  
The study area is within eastern Romania, mainly the Subcarpathian area of Moldavia, which includes the hydrographic basin of the Bistrita River (Figure 1a) and the geographical unit called Cracau-Bistrita Depression, where the Middle Bronze discoveries are grouped (Figure 1b). Owing to the particularities of the relief and natural resources [2], such as fertile soils and pastures, but also salt springs [3], this area was intensively frequented in prehistoric times [4]. The Bistrita Valley is also an important hydrographic artery of the Subcarpathians, so some sectors register a high density of settlements. It also represents an important communication route [5] that connects the east and the west of the Eastern Carpathians, benefiting from smaller communication arteries, branched on either side of the main valley. Figure 1: Bistrita River basin: (**a**) localization on Romanian territory; (**b**) discoveries specific to the Middle Bronze Age; (**c**) Costis and Monteori sites (1. Bacau—_Margineni_; 2. Bodesti de Jose—_Cetxtuia Frumusica_; 3. Borlesti—_Dealul Cucului_/Dealul Nucului_; 4. Borlesti—_Dalul Runcu_; 5. Costisa—_Dealul Biserici/Piciorul Moenii_; 6. Costisa—_Dealul Stanciului_; 7. Costisa—_Cetxtuia_; 8. Itsti—_Lac Lilieci_; 9. Luminis—_Deleni_; 10. Piatra-Neamt—_Bata Doamnei_; 11. Piatra-Neamt—_Lutarie_; 12. Piatra-Neamt—_Pietrica_; 13. Piatra Soimului—_Horodistea/Capul DALUui_; 14. Podoleni—_Dealul Tsuhui_; 15. Racova; 16. Silistea—_Vatra Satuli_; 17. Silistea—_Pe Cetxtuie_; 18. Traian—_Dealul Fantanilor_; 19. Valeni—_Cetxtuia_; 20 Hoisesti—_La Curmlatur_ 1). Although sporadic traces of habitation have been identified in the mountainous sector of the Bistrita valley, there are a series of archaeological discoveries in this area that illustrate and support the idea of using this transit space during prehistoric times (Figure 1b). The intensity of habitation in the middle and lower basin of the Bistrita River varies from one chronological level to another, but for the Middle Bronze Age, the period of interest for this study, 20 discoveries are known, some of which were investigated by archaeological surveys and excavations or by field research (Figure 1c). Although not many sites specific to the Bronze Age are known in the mountainous area of the Bistrita basin, it certainly was an area of transit or resources procurement. The working hypothesis can be supported by, among other things, the existence of an intermediate site at Chiriteni (Hangu commune), where two archaeological complexes are documented and dated to the Bronze Age [6]. Such presences were also reported at Dirtu (Hangu commune), where a stone ax attributed to the Bronze Age was discovered [7]. Isolated metal finds [8] (Bicaz--_Neagra Cociaurei_, Bicazz--_Capsa_, Bicazz-Chei, Bistrita, Grintjes, Tulghes, Viisoara) attributed to the Middle [9] and Late [8] Bronze Age were also reported. All these discoveries highlight the frequenting of the mountainous area by prehistoric communities. The mountainous sector is an important area for a number of raw materials such as igneous and metamorphic rocks resulting from Neogene volcanism in the Eastern Carpathians. A recent study carried out on the lithtic material illustrates the presence of these types of rocks in proportion of 10-15% in the Costisa--_Cetatuia_ settlement [10]. The parallelism of the valleys and hills facilitates longitudinal circulation, but the transversal routes that could have represented old connecting roads between the east Carpathian and intra-Carpathian areas are not to be excluded [11; 12]. Additionally, the settlement from Paulenti--_Dambul Cetatii_ (Harghita County), dated between 1830 and 1680 B.C. [13], must be discussed; this site being relevant to the present study by its positioning in a strategic area, located to the west of the Eastern Carpathians, as well as through the presence of some discoveries relevant to the present study. In the mountainous sector, another important resource for the Eneolithic period is found [14].