Erotic royal seal shows Anglo-French entente was once extremely cordiale

A semi-pornographic royal seal, discovered in a field in East Anglia, is providing historians and archaeologists with vital clues to the life of one of the Dark Ages' most bizarre celebrities.

Queen Balthild is now thought to have been born an Anglian aristocrat, who was then sold into slavery. She married the King of the Franks, became a ruthless ruler and murderer, but was finally made a saint before she died.

With her somewhat intimidating name - Balthild means literally "Bold Battle" in Anglo-Saxon - she has long been an enigma to scholars of Dark Age history. But the discovery, by a metal-detector enthusiast, of her royal seal matrix buried in a field in East Anglia is shedding new light on her extraordinary story.

The gold seal matrix, which was originally attached to a ring, is one of the most important Dark Age artefacts ever found in Britain. On one side is a human face with her name inscribed around it in Frankish form. On the other side are two naked figures thought to portray Balthild and her husband, the Frankish (French) king, having sex. The respectable side, according to this month's BBC History magazine, was used to seal official documents, while the reverse was no doubt used to seal more private correspondence between royal husband and wife.

An analysis of her name suggests that Balthild was a member of one of the Anglian (rather than Saxon) tribes and therefore almost certainly came from an Anglian area, namely Suffolk or Norfolk.

Second, the field in which the seal matrix was found - just a few miles east of Norfolk's county town, Norwich - has been yielding further Anglo-Saxon finds, suggesting that the matrix came from a long-vanished settlement, conceivably associated with her descendants.

Reconstructing Balthild's early life has long been a challenge to scholars, but new research now suggests that she was born around 627 and that she may well have been connected in some way to the last pagan king of East Anglia, a usurper called Ricberht who was ousted by his Christian rival Sigabert, the rightful heir to the throne, with French help. The victorious Sigabert (whose name, aptly, means "Shining Victory") had invaded East Anglia after spending several years at the court of the Frankish king.

As a young girl, Balthild was sent to the same French royal court as a slave - perhaps as a relative of the defeated Ricberht.

She joined the household of the king's chief administrator, Erchinoald, whose unwanted sexual overtures she rapidly learnt to resist. Just as well - for she soon met the French king, Clovis II. The pair appear to have fallen for each other and were married in 648. They had three sons, each of whom later became a Frankish king.

In 657 Clovis died, and Balthild took over as regent until her son came of age. By all accounts she was a ruthless ruler: as part of a continuing struggle with the church, she seems to have been responsible for the murder of at least nine French bishops. When her son Clothar came of age in 664, Balthild's rule ended - and she was virtually imprisoned in a convent. There she dedicated herself to a life of unexpected piety until her death in 680.

The wedding present from Clovis - the royal seal ring - must have been one of her most treasured and intimate possessions. How it ended up in a field near Norwich is a mystery. But it is conceivable that it was returned to her East Anglian family estate after her death. An analysis of all the other finds from the field - brooches, a finger ring, a pendant, belt fittings - does indeed hint that a high-status Anglo-Saxon residence once stood on the site.

For Dr Andrew Rogerson, a leading archaeologist at Norfolk Museums and Archaeology Service, which has rec- orded all the finds from the area, the seal is simply "the most extraordinary single object" he has ever examined.