There are a little less than 200 portal tombs surviving in Ireland, and Poulnabrone in Co Clare is seen by many as the classic example of this form of megalithic tomb.
It comprises a stone chamber with a pair stones at the north end forming an entrance or portal, hence the term portal tomb. These portal stones are tall, so that the large capstone is raised high above the entrance and falls gradually towards the rear of the chamber.
Poulnabrone sits on a limestone plateau in the Burren, a name that derives from the Irish word boireann, meaning a rocky place.
This landscape of bare rock and terraced hillsides has its origins in the carboniferous period over 300 million years ago. Now standing high above the surrounding countryside, it was formed in the warm, shallow seas of the Carboniferous ocean. It emerged from the seabed over 50 million years, and a layer of shale that shielded the limestone for millions of years was eventually removed during the ice age.
Today the tomb appears to be growing out of the rock, as if it is in tune with the environment around it. However, when the tomb was originally constructed, the landscape here looked very different. Pollen studies have shown that the area was densely forested with oak and hazel at the time the tomb was constructed during the Neolithic.
Today the tomb sits on the exposed limestone pavement, but we know that there was about 25cm of soil cover over the rock at the time it was constructed. When the first farmers began to clear the woodland to create their fields nearly 6000 years ago, this contributed to the large-scale erosion of the soil that has taken place here over the intervening millennia.
Despite the dramatic erosion of the overlying topsoil throughout this area, when it was excavated in the 1980s, archaeological remains were still preserved within a thin layer of soil within the chamber, and the fissures within the underlying bedrock.
The excavations found the remains of at least 35 individuals buried within the chamber of the tomb. These represented both male and female as well as a wide range of age groups. The excavations also uncovered sherds of pottery, stone tools, including a polished stone axehead, as well as bone and stone pendants – that were probably deposited in the tomb as grave goods with the deceased.
Radiocarbon dating of the remains suggest that the tomb was built around 5800 years ago and continued to be used as a place of burial for around 600 years.
One of the oldest monuments known in the Burren, Poulnabrone has become symbolic of one of the richest archaeological landscapes in the country, and across the world, this remarkable megalithic tomb has become an iconic image of early prehistoric Ireland.
Poulnabrone is National Monument in state care since 1985 and is managed by the Office of Public Works.
