Prehistoric timber circle from Holme

Seahenge

Prehistoric timber circle from Holme

In the summer of 1998 the shifting sands of Holme beach on the north Norfolk coast revealed something extraordinary. Preserved in the sand were the remains of a unique timber circle dating back over 4000 years, to the Early Bronze Age. Although discovered on a modern beach, the circle was originally built on a saltmarsh, some distance inland.

The discovery captured the imagination of archaeologists and public alike and the site soon became known as ‘Seahenge’. The timbers came from a circle 6.6m (21 ft) in diameter, comprising 55 closely-fitted oak posts, each originally up to 3m (10 ft) in length. At the centre of the circle was a great upturned tree stump. Scientific dating methods showed that the trees were felled in the spring or early summer of 2049BC. Whilst we can never be certain why the site was built, it was probably used following the death of an important person, with a body laid out on the upturned stump so birds and animals could pick the bones clean. They were removed for burial elsewhere. We do know that after only a short period of time, the entrance to the circle was sealed.

The changing landscape of Seahenge

Reconstruction drawing of the salt marsh where Seahenge was originally built

The land where the circle was built in 2049BC would have been saltmarsh, protected from the sea by sand dunes and mud flats Mixed oak woodland lay close by and the saltmarsh was probably used for grazing animals. In the Early Bronze Age, the local area was becoming waterlogged . The oak trees used to construct the circle show signs of struggling to survive in the increasingly wet conditions.

In the centuries that followed the building of the circle, the

saltmarsh was covered by freshwater reed swamp, colonised by rushes and alder trees. This swampy area created a thick layer of dark peat which covered the remains of the timbers, protecting them from decay. Over the last 3000 years, the sea has

encroached on the land as the protective barrier formed by the dunes moved steadily inland. The site was eventually covered by sand, killing the plants and trees.

The protective layers of peat sealing the timbers were gradually worn away by the action of tides and storms. As soon as the

timbers were exposed to the air, they began to decay. Holme beach is located within a very sensitive nature reserve that is home to internationally important populations of migratory birds. These are easily disturbed by people. No archaeological remains can be seen at the site today.

The builders of Seahenge

Seahenge was built by people living and farming near the

saltmarshes. Norfolk has produced rich archaeological evidence from this period, including the nearby settlement at Redgate Hill, Hunstanton. 4000 years ago, in the Early Bronze Age, people

would have lived in small farming communities, growing crops such as wheat and barley and grazing sheep and cattle. Their homes were simple roundhouses, with walls of wattle and daub and roofs of thatch or turf. Everybody in the family would have helped with the chores and many of the things they used and owned would have been homemade, including their clothes.

Everyday equipment such as knives and arrowheads were made from flint, a

naturally sharp stone. Bronze Age people also carved

wood, bone and antler to make tools and jewellery. Simple pottery vessels were used for cooking and

storage, whilst finer pots such as the intricately decorated beakers were probably used for special occasions, including burial. Metal tools were introduced from the continent just a few generations before Seahenge was constructed. Axes previously made from polished stone were now produced in bronze. Some of the earliest metalwork took the form of jewellery. Bronze objects would have been highly valued.

Why did they build it?

Up to 50 people may have helped to build the circle, possibly a local tribe coming together to mark a special occasion – perhaps the death of an important member of the community. Across Britain, many ceremonial monuments survive from this period. Some are associated with burials, whilst others were used for community ceremonies spanning centuries.

Although we can never be certain why Seahenge was built, many archaeologists think that the upturned stump supported the body of an important person, a process known as ’excarnation’. Birds and animals would have been allowed to pick the body clean before the bones were removed elsewhere for burial. As with many ceremonial sites of this period, the circle may also have served as a simple astronomical calendar, marking the Midwinter sunset and Midsummer sunrise.

Excavations at Holme beach (courtesy of Archant)

Discovering and excavating Seahenge

The discovery of an unusual arrangement of timbers on Holme beach was first reported in spring 1998. Archaeologists quickly recognised the significance of the site and the threat posed by the sea. Following an initial investigation, it was decided to excavate the circle and remove the timbers from the beach. With funding from English Heritage, excavations by Norfolk Archaeological Unit took place in 1999. Conditions for the archaeologists were difficult. The site was covered by tides and only accessible for between two and four hours a day. There were also a number of protests on the beach by people opposed to the removal of the timbers. The excavations revealed a wealth of information. The timbers for the posts were cut nearby, dragged to the site and lowered into a trench. Some posts were trimmed on arrival. When the circle was completed, all of the timber posts still had bark attached. A few posts also had bark on the inside, including the post placed opposite the entrance to the circle. This entrance was blocked by a post soon after the site was built. All bark had been removed from the central stump and tow holes cut in it.

Viewed from outside, the circle would have looked like the bark-covered trunk of a great tree. By contrast, the inside would have glowed brightly from the freshly cut wood. At the centre of the circle stood an enormous upturned stump. When the stump was finally lifted, there was no trace of the body that some archaeologists expected to find underneath. Instead, they discovered a length of twisted honeysuckle rope used to drag the stump into place. The circle was dated to the year 2049BC through a study of the tree rings on the timbers (dendrochronology) and the scientific technique of radiocarbon dating.

Conserving and studying Seahenge

As soon as they emerged from the sands of Holme beach, the timbers began to decay. Originally preserved by a thick layer of peat, they were now exposed to a number of damaging effects

including sea water salts, wood-boring molluscs and worms. The timbers also suffered from the twice daily wetting and drying by the tide.

Conservation of the central stump at Flag Fen (courtesy Archant)

Once removed from the beach, the timbers were taken to the Bronze Age Centre at Flag Fen, near Peterborough. Here they were placed in fresh water tanks, the beach mud cleaned off and most of the salts removed.

Central oak trunk being lowered into a tank of preservative wax

The timbers were then laser-scanned to record every detail on their surface. This study of the timbers revealed a wealth of information. The posts and stump all came from between 15 to 20 oak trees felled in spring 2049BC. A number of posts came from the same tree. The trees had been cut down and shaped with bronze axes. The marks left by up to 50 individual axes were preserved on the surface of the wood. This came as a surprise to archaeologists, as the circle dates from a time when metal tools had only been in use for a few generations and were thought to be rare.

In 2003 the timbers were transferred to the Mary Rose Trust in Portsmouth. A complex conservation project started with them being placed in clean water to remove any remaining salts. They were then immersed in the special wax, polyethylene glycol (PEG), which gradually reinforced the cell structure of the wood. The timbers were then vacuum freeze-dried to remove any remaining water.

Preserved Bronze Age oak timbers on display at the Lynn Museum

Today the unique ancient timbers of Seahenge are displayed for all to enjoy at the Lynn Museum, King’s Lynn. Contact the Museum for further information on the displays or details of our events programme on 01553 775001, email lynn.museum@norfolk.gov.uk, or visit