This tiny gold object was originally part of a finger-ring. It would have been used as a personal seal for pressing a pattern into wax to seal letters.
Both sides could be used as seals. One has an image of a woman's face surrounded by the name 'BALDEHILDIS'. The other depicts a woman and a man under a cross, possibly having sex.
The seal probably dates from the seventh century AD, since it is similar to Frankish coins of this period. We also know of someone called Baldehildis who lived at this time. According to a late-seventh century manuscript, the Vita Sanctae Balthildis, she was an English woman who was captured and taken to France, where she married Clovis II, the Frankish king, in about AD 648. After his death, she ruled as Queen-regent. During this time she founded a monastery at Chelles, near Paris, retiring there in about AD 664/5. She was made a saint after her death in about AD 680.
Seal rings like this are very rare. They belonged to important people such as kings, bishops or abbots. If this seal really did belong to the Baldehildis written about, then it shows an important connection between the rulers of East Anglia and of France in the seventh century AD.