The settlement of the territory of north-eastern Serbia by the representatives of the Coţofeni culture began during the second half of the IV millennium, probably under the pressure of invading tribes from Euroasian steppe. This territory extended over Transylvania, Banat, Oltenia and Muntenia (Map 2). On the territory of Serbia they settled from the Djrerdap gorge up to the Mlava river to the west, and through Kučajske mountains, Bor, Zaječar and further to the south, up to Niš. Aspecific symbiosis occurred on the territory of Serbia between the Coţofeni and the Kostolac cultures. According to the results of the latest project of re-identification, the number of Coţofeni-Kostolac sites and settlements increased to 76. After all the sites were re-identified and georeferenced, with consideration of the surrounding landscape, hydrography, geomorphology of the terrain and the character of the ceramic production finds, we believe that there is a need for re-analyzing specific aspects of the cultural and geographic development not only of settlements, but of the entire Coţofeni-Kostolac cultural phenomenon. In this paper we considered three archaeological sites in the Nišava valley, given that re-identification work over the past several years yielded new information (Bubanj-Staro Selo, Velika Humska čuka and Donja Vrežina). The topography of Coţofeni-Kostolac settlements on the territory of north-eastern Serbia, the Serbian part of the Danube valley and its hinterland, is characterized by diversity of position (location above sea level and landscape placement), types of houses and economic survival. In the 70’s of the last century sites were identified that are located in very inaccessible terrain, which in particular cases has an slope incline of 45°, where the number of such settlements in the meantime increased to nine. They are represented by Kulmja Škjopuluji in Klokočevac and Pjatra Kosti in Crnajka (T. I/1-2; Map 1/9), followed by Vratna -Veliki most (T. I/ 7; Map 1/33), Bogovina-above a cave (T. I/ 4; Map 1/8), Jezero (T. I/ 3; Map 1/12), Kljanc (T. I/3; Map 1/11), Turija-Stenje (T. I/ 6; Map 1/22), Mokranjske stene-quarry (T. I/ 5; Map 1/39) and Bolvan (T. I/ 8; Map 1/66). These settlements have several other common elements, the most important being that each one of the elevated settlements is positioned on the rocky peak of a canyon, in places where smaller rivers or brooks flow into a larger river. We can suppose how the selection of such positions was of strategic importance, given that in the mountainous area of north-eastern Serbia the system of waterways and river valleys represents communicational links from prehistory to modern times. The second common characteristic of these settlements is the rocky massif which provided the foundation for their erection. The rock foundation in the majority of cases is of limestone origin and is well suited to artificial nivelation into terraces atop which surface structures could be built using wood covered with mud (Jezero, Kulmja Škjopuluji, Pjatra Kosti, Vratna, Bogovina). The third shared characteristic is that one or more caves are usually located in the immediate vicinity of settlements. An example of the symbiosis of cave and hill fort Coţofeni-Kostolac settlements is the vicinity of the Zavojsko jezero near Majdanpek. So far two hill fort settlements, Jezero and Kljanc (T. I/3; Map 1/11-12), were identified in this area, built on limestone cliffs above the Mali Pek river. The Rajkova cave (Map 1/14), Paskova cave and Kapetanova cave (Map 1/13) are located in their immediate vicinity, in which the remains of anthropogenic activity were discovered. The Kapetanova cave provides stratigraphy of over 3 m high, which represents a rare case for Coţofeni-Kostolac cultural sites. This fact does not only indicate its long-term use, but could provide the answer to the genesis and duration of this cultural phenomenon on the territory of the Serbian part of the Djerdap hinterland. The fourth shared characteristic which links these settlements is their dominant position in the landscape. Given that their position and appearance are readily visible from a considerable distance, they probably were not used for hiding, but for making their position prominent. We suppose that pastoral communities emphasized in this manner their control of mountain crosspass and roads, particularly in places where rivers exit narrow canyons in important communications paths to the Crni and Beli Timok, Pek and Danuber rivers. The other Coţofeni-Kostolac type settlement on the territory of north-eastern Serbia is represented by settlements that are positioned on smaller hills or on gentle slopes that on the average range between 336 and 210 m above sea level. The only fortified hill fort settlement discovered so far, Čoka lu Balaš near Krivelj (Map 1/3) belongs to this group. The archaeological sites Velika Čuka i Neresnica (Map 1/23), Smiljkova glavica in Štubik (Map 1/31) and Ćetaće in Kovilovo (Map 1/38) are located on wide and flat, elevated plateaus that dominate up on river valleys. Judging by the considerable surface that they occupy, their position and surroundings for these two settlements, we can suppose that they could have been used for wintering places or points for gathering of flocks and shepherds during pauses between seasonal migrations. They are primarily characterized by the natural surroundings of smaller hills and larger river valleys, as well as the relatively low above sea level elevation on which they are located. Such “seasonal stations or checkpoints” on which larger groups of shepherds could gather with their flocks during the winter months represented important locations in the lives of pastoral communities. During the warm summer period, homesteads with stable architecture are abandoned because of migrations into mountain areas, where favourable grazing areas area located. Certain groups of shepherds during autumn returned to these settlements en route to lowlands and river terraces, while other groups probably continued their journey to gathering centres in valleys near the Danube and the Timok rivers. The next type of settlement belongs to high, multi-layered settlements (Arija baba-Košobrdo, Čoka Kormaroš, Field of Z. Brzanović, Varzari and Smedovac-Grabar-Svračar) which represent sunbathed dominant positions, with a good view of the surrounding area, well suited to long-term occupation. Settlements on high elevations of this type are usually linked with landscapes that predominate in grazing areas and in which there are no large forests. The last type of Coţofeni-Kostolac settlement is characteristic of lowland settlements positioned on river terraces. The settlements on the right bank of the Danube, around Ključ (Kladovo- Brodoimpeks, Mala Vrbica, Zbradila-Fund, Korbovo- Obala, Vajuga-Pesak, Jakomirski potok estuary, Velesnica, Ljubič evac-river bank, Ljubičevac-Island, Brzi prun, Slatinska reka estuary, Knjepište, Ruženjka, Kusjak-Bordjej, Kusjak-Motel, Kusjak-Vrkalj), represented points at which shepherd’s flocks could remain for longer periods, waiting for favourable conditions for crossing to the other side of the river. This assumption is based on old maps predating the construction of the accumulation lake. These maps indicate that in the immediate vicinity of these settlements were located small sand islands linked to the river bank, pointing to shallows and crossing points. These sections of the river bank, during prolonged droughts or during cold winters, when ice was formed, could have been places where the river was crossed from one side to the other. Residential architecture cannot be precisely defined, given that the discovered remains of houses are very meagre and lack sufficient elements for reconstruction. The most recent excavations on the Bubanj-Staro Selo settlemant at Niš, indicate an identical type of architectural construction as discovered at Gomolava and Bordjej which represents structures that are characteristic for lowland areas. Houses in hill fort settlements built on artificial terraces have been mostly devastated by erosion, so that judging by the impressions of wooden structures and wattle and daub, as well as the remains of hearths, it can be asserted that these were residential structures. Numerous studies so far noted that based on the stylistic and typological characteristics of ceramics on archaeological sites in Timočka Krajina it is possible to distinguish between two phases of the Coţofeni group, where the first is dominated by ornamental techniques of carving that are characteristic of the Coţofeni group, and a later phase in which this style is mixed with the furchenstich, as well as other Kostolac cultural elements (furchenstich, certain types of ceramics, etc.). The fact is that the majority of Coţofeni-Kostolac group sites in eastern Serbia have not been excavated, or have only been partially excavated, and that no vertical stratigraphy had been observed, where no stratigraphic relationship between stylistic-topological characteristics of older ceramics (Coţofeni) and the more recent phase (Coţofeni-Kostolac) have been established. These are mostly settlements in which ceramics were observed with elements both of the Kostolac and the Coţofeni group, or only with elements of the Coţofeni group, while settlements with only Kostolac ceramics have not been identified. Therefore, in Serbia it is only possible to distinguish between sites where furchenstich ornamentation has been observed and those where this type of ornamentation still has not been observed. Still, it is unclear whether this distinction can be applied to period assignment, or whether it is in fact caused by settlement of different populations in different regions of Eastern Serbia - the Kostolac region from the west and the Coţofeni group from the East. In Romania, however, vertical stratigraphy was observed at several settlements where development phases were observed of the Coţofeni group, so that based on the stratigraphy at those sites, with certain caution, it is possible to draw conclusions about the development of the Coţofeni-Kostolac group in eastern Serbia. Settlements without any furchenstich ornamentation would be assigned to the older phase (Coţofeni group) where ceramics characteristic of the Coţofeni group have been observed, although observed shapes and ornaments are usually associated with the furchenstich technique and the more recent phase of the group. The most frequent type of vessels at sites in eastern Serbia are amphorae with extended funnel shaped necks, ornamented below the neck with carved lines or with stamped ornamentation (fig. 6, 21, 38, 64, 71, 89, 98-100, 104, 109, 115, 116, 134), fishbone shape impressions (fig. 4, 28), and in the more recent period furchenstich ornamentation or point impressions (fig. 9, 20, 25, 140), with a tongue shaped or vertically perforated handle, tunnel shaped or horse-shoe shaped handle below the rim (fig. 6, 9, 20, 21, 51, 63, 100, 126, 134, 88, 115 ). The second characteristic type of vessel are semi-spherical bowls with deeper recipients, with flat rims (fig. 11, 12, 23, 27, 29, 52-54, 57, 59-60, 74, 79, 81, 82, 90, 91, 95, 113, 124, 125, 131 and 145), or with shallower recipients, with a slanted, triangular rim or T-shaped profiled rim (14, 19, 133 and 146). Such vessels are characteristic for both phases, because they are ornamented, besides vertical ribs, with carves, and with furchenstich ornamentation (fig. 23, 68, 81 and 82). The third type of vessels are semi-spherical bowls with contracted rims creating a nearly spherical shape. They can be ornamented with vertical ribs on rims (fig. 148) in combination with pinholes (fig. 17), carves (fig. 61, 84, 85) or line impressions (fig. 132). Less frequent vessels on the territory of northeastern Serbia are biconical or spherical goblets, followed by pare-shaped goblets with a single handle, larger pare-shaped amphorae with an extended or conical neck, with small handles below the rim, ornamented with a series of carves (fig. 39, 86), as well as barrel or spherical pots ornamented with carves, horizontal tapes or circular impressions (fig. 45-47, 141, 142). The appearance of ropeshape ornaments is very significant, given that they appear in Rumanian finds in the second phase of the Coţofeni group, and most frequently in the third phase. This ornament was sporadically observed in the far south, on the Dikili Taš site on the northern shore of the Aegean sea, in level 6, which according to the author belongs chronologically to the Bubanj-Hum II group and the Kostolac group. Its presence at sites in eastern Serbia can be linked to the older phase at the majority of settlements, except in the case of Grabar-Svračar, as these ceramics were not found alongside ceramics with furchenstich. The largest number of sites with only Coţofeni elements on ceramics have been observed (34), but it is indicative that only a few have been excavated. 28 sites with Kostolac group elements were noted, while 17 unspecified sites in which the period cannot be precisely defined have been identified. According to the stratigraphy of several of the mentioned sites in western Bulgaria, in the Morava valley and in southern Romania it can be concluded that the Coţofeni group (northeastern Serbia and Romania) and the Coţofeni-Kostolac group (Morava valley and western Bulgaria), in all of the mentioned regions, was preceded by the Černavoda III group, and was superseded by the Vučedol culture and the Bubanj-Hum II group in the Morava valle and the Struma valley, and the Glina II-Schnekenber group in Oltenija and the territory of Transylvania and the southern Carpathians. Analysis of the distribution of settlements and stylistictopological characteristics of ceramics from all of the settlements led to the conclusion that the oldest settlements, without ceramics with furchenstich ornamentation, were established in Ključ in Negotinska Krajina, leading to the assumption that the representatives of the Coţofeni group came from Oltenia and from the southern Carpathians. A large number fo sites west of Ključ, along the Danube, at which ceramics with furchenstich ornamentation were noted, point to the direction of expansion of Kostolac elements, from Banat, Branicevo and Stig. The influence of the Kostolac group was very strong starting in the Coţofeni II phase, even in Romanian sites, given that in Transylvania and in the southern Carpathians a large number of ceramic finds were found with furchenstich ornamentation, while it is interesting that only sporadic appearances were noted in Oltenia. It is clear that Coţofeni group settlements represented a certain barrier to the expansion of these elements to the east. With the formation of the Coţofeni-Kostolac group which was created through contacts between representatives of the Coţofeni to the east and the representatives of the Kostolac group to the west and north-west a short period of coexistence occurred on this territory. Absolute dating of the chronological framework of the Coţofeni-Kostolac group in the Danube valley and in eastern Serbia can only be assigned indirectly, as there is no carbon dating available from these sites. According to J. Bojačijev, phase II-III of the Coţofeni group (4400-4300 bp) can be assigned chronologically approximately to the same period as the Kostolac group (4500-4100 bp), and if we suppose that the Coţofeni-Kostolac group occurred a little while after the occurrence of the Kostolac group, it can be concluded that the Coţofeni-Kostolac group existed at the end of the IV and the first half of the III millennium BC, although it is possible that it continued even later in particular regions. The results for the oldest and the middle phase of the Kostolac cultural group at Gomolava range between 3038-2903 BC and 3108-2877 BC, while the Kostolac culture at the Streim and Vučedol sits was dated 3310-2920 BC, as is the approximate dating of settlements of this group in Pivnica (3042-2857 BC). All the dating of Kostolac group sites indicate that this cultural group occurred and developed in the period of the last quarter of the IV and the first half of the III millennium BC, which would chronologically assign the Coţofeni-Kostolac group in the Morava valley and Timočka Krajina to the end of the IV and the start of the III millennium BC, and to the ensuing period. [Projekat Ministarstva nauke Republike Srbije, br. 177020: Arheologija Srbije: Kulturni identitet, integracioni faktori, tehnološki procesi i uloga centralnog Balkana u razvoju evropske praistorije]