Nestled within the valleys, hills and open fields of Wales, lies one of Western Europe’s most remarkable collections of prehistoric Neolithic burial chambers.

These ancient structures, dating from 4,000 to 2,000 BCE, stand as enduring testaments to early human culture and belief systems.

There are about 250 examples scattered across the Welsh landscape – though experts estimate this represents only a third of the sites that once existed.

Professor of Archaeology at the University of Coimbra and research fellow at Liverpool University George Nash explores this transformation in his book The Neolithic Tombs of Wales.

It looks at the transition from hunter-gatherer societies to farming communities.

This marked a pivotal shift in human history, fostering more permanent settlements and rituals that celebrated the deceased.

Prof Nash highlighted the profound changes in burial practices over the 2,000-year span of the Neolithic period.

“Two thousand years is a long period, even for us today,” Prof Nash said.

“Imagine how religious practices have evolved since the birth of Christianity.

“Similarly, we see changes in Neolithic architecture and burial methods, from natural caves to constructed stone tombs and earthen mounds, and from simple burial to cremation and excarnation… the process of exposing bodies to the elements until only bones remain.”

This practice of ritual burial is believed to have originated among early Neolithic groups in the “Fertile Crescent” – a region encompassing parts of modern-day Turkey, Israel, Syria and Lebanon – before gradually spreading westward.

The process took at least 600 years.

“With this westward spread came not only burial traditions but also tools, pottery, and jewellery intended to accompany the dead into the afterlife,” Prof Nash explained.

“Though no written evidence survives, these artefacts suggest an early belief in an afterlife where such items might be needed.”

The majority of Welsh burial sites are located near the coast, a pattern Prof Nash attributes to the strategic advantages these areas offered.

Proximity to the sea allowed Neolithic communities to sustain themselves with fishing and marine resources, crucial supplements in case of crop failure or livestock loss.

The availability of stone in coastal regions further contributed to the preservation of these monuments.

“The remoteness of these areas, coupled with their marginal agricultural value, helped shield many sites from modern development and agricultural practices,” Prof Nash noted.

“This stands in contrast to other parts of Britain and Europe, where road building and field-clearance during the 18th and 19th centuries caused widespread destruction of these monuments.”

DNA evidence suggests that the earliest monuments, such as portal dolmens (or cromlechs in Welsh), were reserved for society’s elite.

Over time, larger communal tombs emerged, reflecting a shift toward burying extended family groups or community members.

“One striking example is the Parc le Breos Cwm burial chamber on the Gower Peninsula,” he said.

“Situated in a secluded valley, this trapezoidal monument contains five chambers that housed the remains of approximately 40 individuals, categorized by age, gender and even species – including dogs.”

Prof Nash concluded: “Wales offers a unique lens into the Neolithic world, providing insights into the lives and beliefs of its first farmers.

“These enigmatic stone monuments represent a window into a past where no written accounts are available, and evidence is often reduced to a few stones, scattered pottery shards, and fragmentary human remains.

“From this limited assemblage, archaeologists can say a lot”.