Battle of Posentesbyrg

History & Significance

The Battle of Posentesbyrg (Posentes byrg) was fought in AD 661 between the West Saxons under Cenwalh and the Mercians under Wulfhere. It was a victory for the Mercians and Cenwalh was forced to relinquish the territory he had gained from the Britons in Somerset. The exact modern location of the battle is uncertain.

In 658 Cenwalh's West Saxons met the Britons for a climactic battle at Peonnum. The Saxons were victorious, and Cenwalh advanced west through the Polden Hills to the River Parrett, annexing eastern and central Somerset. Geoffrey Ashe suggests that Cenwalh's ultimate goal may have been gaining control over the valuable Glastonbury Abbey. Cenwalh's fledgling kingdom in Somerset was probably ruled from Glastonbury but his tenure there was brief. Wulfhere of Mercia ousted him in AD 661 having defeated him at the Battle of Posentesbyrg.

The battle site is usually considered to have been Pontesbury, based on the similarity of the name and its translation by Æthelweard, Ingram and others. There is no other place-name in Britain which bears any resemblance, but Cenwalh fighting at Pontesbury makes little sense in the context of him establishing a kingdom in Somerset. If the battle was in Shropshire, for an unknown reason he marched his army considerably more than a hundred miles to the north, leaving his embryonic Somerset kingdom vulnerable.

David Cooper posits that the battle was actually fought at Ponter's Ball, an ancient embankment about a mile to the south-east of Glastonbury Tor. Almost a mile in length, this defensive dyke is aligned north-to-south and crosses a piece of raised ground which, in the seventh century, provided the only access by land to the Isle of Glastonbury. Posentes does not translate. Cooper suggests that it may be the name of a chief, corrupted to Ponter's on modern maps, and that 'ball' is a corruption of the Old English balc, which translates as a balk, beam, bank or ridge.

Timeline of the Anglo-Saxon invasion and takeover of Britain

The ground they fought on

The site of Battle of Posentesbyrg lies on Lias Group, bedrock that formed in the Aalenian. The rock here is mudstone, siltstone, limestone and sandstone.

Frequently Asked Questions

Scheduled Monuments near Battle of Posentesbyrg

Duck decoy, 590m south west of Rice Farm

Scheduled monument · ~1.8 mi

Duck decoy, situated 590 metres south west of Rice Farm in Somerset, is an ancient monument representing a specialised form of waterfowl management dating to the early modern period. The site comprises the physical remains of a decoy system, a form of trap designed to capture wild ducks and other…

Duck decoy, 820m SSW of Little Huckham Farm: the western of three decoys on Walton Moor

Scheduled monument · ~3.1 mi

Duck decoy, 820m SSW of Little Huckham Farm, is a seventeenth-century wildfowl trap situated on Walton Moor in Somerset. It forms part of a group of three decoys on the moor, representing the westernmost example of these structures used for the systematic capture of wild ducks and other waterfowl…

The Tribunal

Scheduled monument · ~3.6 mi

The Tribunal is a timber-framed building of fifteenth-century date located in Chardstock, Somerset. The structure exemplifies the domestic architecture of the late medieval period, with its characteristic half-timbered construction and jetted upper storey indicative of prosperous merchant or gent…

NotFromUtrecht / CC BY-SA 3.0 / Wikimedia Commons

Glastonbury Abbey

Scheduled monument · ~3.7 mi

Glastonbury Abbey is a ruined Benedictine monastery located in the town of Glastonbury in Somerset, England. Founded in the late Saxon period, the abbey became one of England's most important and wealthy religious houses, with its prominence enhanced by claims connecting the site to early Christi…

Gerd Eichmann / CC BY-SA 4.0 / Wikimedia Commons

The Abbey Barn at Abbey Farm

Scheduled monument · ~3.9 mi

The Abbey Barn at Abbey Farm is a medieval stone structure associated with the monastic complex at this location in Somerset. The barn dates from the medieval period and represents the agricultural infrastructure that supported the religious community, serving as storage for grain and other produ…

NotFromUtrecht / CC BY-SA 3.0 / Wikimedia Commons

St Michael's Church, monastic remains, and other settlement remains on Glastonbury Tor

Scheduled monument · ~4.4 mi

St Michael's Church is a late medieval tower situated at the summit of Glastonbury Tor in Somerset, constructed in the fifteenth century as a replacement for an earlier church dedicated to the same saint. The tower, which stands approximately thirty feet high, is built of local stone and represen…

Matthew Knight Photography / CC BY-SA 4.0 / Wikimedia Commons

Other Early Medieval Battles

Battles near Battle of Posentesbyrg

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• Battle of Posentesbyrg · Wikipedia