Long barrow

Long barrows are a style of monument constructed across Western Europe in the fifth and fourth millennia BCE, during the Early Neolithic period. Typically constructed from earth and either timber or stone, those using the latter material represent the oldest widespread tradition of stone construction in the world. Around 40,000 long barrows survive today.

The structures have a long earthen tumulus, or "barrow", that is flanked on two sides with linear ditches. These typically stretch for between 20 and 70 metres in length, although some exceptional examples are either longer or shorter than this. Some examples have a timber or stone chamber in one end of the tumulus. These monuments often contained human remains interred within their chambers, and as a result, are often interpreted as tombs, although there are some examples where this appears not to be the case. The choice of timber or stone may have arisen from the availability of local materials rather than cultural differences. Those that contained chambers inside of them are often termed chambered long barrows while those which lack chambers are instead called unchambered long barrows or earthen long barrows.

The earliest examples developed in Iberia and western France during the mid-fifth millennium BCE. The tradition then spread northwards, into the British Isles and then the Low Countries and southern Scandinavia. Each area developed its own variations of the long barrow tradition, often exhibiting their own architectural innovations. The purpose and meaning of the barrows remains an issue of debate among archaeologists. One argument is that they are religious sites, perhaps erected as part of a system of ancestor veneration or as a religion spread by missionaries or settlers. An alternative explanation views them primarily in economic terms, as territorial markers delineating the areas controlled by different communities as they transitioned toward farming.

Communities continued to use these long barrows long after their construction. In both the Roman period and the Early Middle Ages, many long barrows were reused as cemeteries. Since the sixteenth century they have attracted interest from antiquarians and archaeologists; it is from the excavations of the latter that our knowledge about them derives. Some have been reconstructed and have become tourist attractions or sacred sites used for rituals by modern Pagan and other religious groups.