About 4900 BC, central Europe continued to be occupied by peoples descended from LBK communities, such as the Rössen culture in central and southern Germany, the Stroke-Ornamented Pottery culture of eastern Germany and Bohemia, and the Lengyel culture of Poland, Slovakia, and Hungary. These groups followed the same way of life as LBK farmers through most of the 5th millennium BC. An important development of this period is the exchange with Mesolithic foragers of southern Scandinavia, represented mainly by stone axes (Midgley 2004).
The Mesolithic Ertebølle culture is found ca. 5400–3950 BC in the western Baltic area, including southern Scandinavia and northern Germany between the Elbe and the Oder rivers, roughly contemporary with LBK communities to the south. It comprises an older, aceramic phase (ca. 5400–4600 BC), and a younger phase with pottery, T-shaped antler axes, and imported axes. T-shaped antler axes had a wide Neolithic distribution, appearing first in southern regions, like agriculture and cattle. Flint technology was based on blades used to produce arrowheads with a transverse edge, end scrapers with a convex edge, and tanged scrapers with a concave edge (Midgley 2004).
Contacts with other Mesolithic groups of the Atlantic façade and Comb-Ceramic groups in the eastern Baltic are evidenced by their similar pottery, featuring shallow, oval bowls (presumably used as lamps), and pointed-bottom vessels including small beakers and medium and large pots used for drinking, cooking, and perhaps storage. This pottery is only rarely found in groups to the south. Settlements appear in coastal and riverine zones apt for fishing, and comprise large central sites occupied more or less continuously, as well as small, seasonal sites. Burials can be found far from the coast and on high elevations, and consist mostly of inhumations, usually in the extended supine position, with men given knives, daggers and axes, and women ornaments (Midgley 2004).
Megalithic tombs appear in western Europe among post-Neolithic societies along the western Mediterranean but principally expands along the extensive Atlantic façade, reaching from western and northern Iberia, France, Sardinia, mainland Italy, and the British Isles to the Shetland Islands, the Northern European Lowlands and Scandinavia. Tens of thousands of large stone burial monuments were built, using large boulders to form chambers and passages covered with mounds of earth or cairns of stones (Müller 2014).
The first grave chambers start ca. 4700 BC in north-western France, from pre-megalithic monumental sequence and transitional structures, as a response to different influences: the Blique/Epi-Rössen tradition of non-megalithic long barrows of the Passy type were erected in the Paris Basin; the eastern concept of trapezoidal-rectangular long barrows reached the northwest coast of France; and stone cists and early passage graves, similar to Epicardial and Cerny grave traditions further to the south, are found in these and other mounds (Schulz Paulsson 2019).
The culture appears in Corsica and Sardinia as simple dolmens ca. 4200 BC, while on the British Isles it emerges ca. 4000 BC, and in north-central Europe and southern Scandinavia they start ca. 3650 BC within the Funnel Beaker culture, starting on the western coasts of Oland and Gotland. The allées couvertes and gallery graves both developed as of ca. 3600 BC in inland settings from Brittany over to the Paris Basin and to central Germany (Müller 2014). The distribution emphasises the maritime linkage of these societies and a diffusion of the passage grave tradition along the seaway, accompanied by economic and social changes in Europe (Schulz Paulsson 2019).
Most tombs were collective burials, opened repeatedly to bury bones of newer generations, pushing bones of earlier generations aside to make space. They clearly represent ceremonial monuments, where the deceased members of the same community or clan were buried together (Midgley 2004). The high mobility of Neolithic society probably facilitated the diffusion and convergence of the new architectural developments and underlying ideology, but there is also evidence of demic diffusion (Müller 2014).
Samples from Late Mesolithic/Neolithic sites show continuity of I-M170 lineages and previous ancestry; so e.g. in a sample from central Norway (ca. 3940 BC) of hg. I2a1a2-M423 (Günther et al. 2017), in subsequent samples of the Nordic Neolithic, and in samples from the Zedmar culture (ca. 4500–3000 BC), related to Mesolithic Ertebølle, showing typical hunter-gatherer mtDNA U5b1 (Bramanti et al. 2009).
In Neolithic individuals from southern France and Britain there is a greater affinity to the Iberian Early Neolithic farmers than to central European ones. This is confirmed by haplotype matching, consistent with the same ancestral populations bringing the Neolithic to Britain and Ireland. Chronological modelling suggests that NWAN-related ancestry arrived in Britain ca. 3975–3722 BC, marginally earlier in the west and rapidly dispersing to other regions (Olalde et al. 2018; Brace et al. 2019).
The Middle Neolithic resurgence of hunter-gatherer-related ancestry in central Europe and Iberia was driven more by males than by females, evidenced by the expansion of hunter-gatherer-associated Y-chromosome haplogroups I2-M438, R1-M173, or C1-F3393 in seven out of nine male individuals in Iberian Neolithic and Copper Age, and nine out of ten individuals in Middle–Late Neolithic central Europe, including the Globular Amphorae culture (Lipson et al. 2017).
Similarly, there is continuity of Mesolithic I2a2-M436 lineages in the British Isles, with fifteen out of nineteen samples reported in Great Britain (ca. 8750–2500 BC) corresponding to this subclade, at least during the Neolithic probably corresponding to I2a1b1a1a1-L1195 (formed ca. 5100 BC, TMRCA ca. 3600 BC) at least three of them from the south-west (ca. 4000–3500 BC) of subclade I2a1b1a1a1b-L1193 (TMRCA ca. 3500 BC). At least one sample from the centre (ca. 3600 BC) is of hg. I2a1a2a-L161.1, which appears more often among megalithic builders.
Individuals buried in megaliths from the British Isles (ca. 3800–3100 BC) and Ansarve in Scandinavia (ca. 3500–3200 BC) show an ancestry similar to other contemporaneous farmer groups, with a majority of their ancestry related to Early Neolithic farmers and a partial admixture component related to European Mesolithic hunter-gatherers. The genetic connection found between western European Neolithic groups from the British Isles to Scandinavia is driven by NWAN-related ancestry, rather than hunter-gatherer-related ancestry, and seems not to include central European farmers, which suggests a migration along the Atlantic coast (Sánchez-Quinto et al. 2019).
Kinship of buried individuals is reflected in Y-chromosome haplogroups, with only I-M170 lineages reported: at least four I2a1b1a1a1-L1195 out of nine in Scotland, one of them of subclade I2a1b1a1a1b-L1193; at least five out of eight I2a1a2a-L161.1 in Scotland and Sweden, with three I2a1a2a1a1-Y3749/FGC7126 (formed ca. 4900 BC, TMRCA ca. 3400 BC) reported in Ansarve (Sánchez-Quinto et al. 2019). Both subclades may also be related to the Neolithic expansion of Atlantic farmers through the Mediterranean route.
Individuals from megalithic burials in the north (with over-representation of males) do not show systematic differences with geographically proximate non-Megalithic burials. Societal complexity during the Neolithic contrasts with the identification of a highly inbred elite individual in Ireland, strongly suggesting that the elaboration and expansion of megalithic monuments was associated (at least in some regions) with dynastic hierarchies (Cassidy 2018).