Rædwald (reigned about AD 616-624) of East Anglia was baptised under the influence of Ethelbert of Kent, but he never abandoned his pagan gods. The kingdom only became Christian in the 630s, when Sigeberht, already a devout Christian, came to the throne. The 8th-century historian Bede tells how Sigeberht invited Bishop Felix to the kingdom from Rome. Felix taught for 17 years at Dunwich, on the Suffolk coast, where he founded a bishop’s seat, making it one of the most important religious centres in East Anglia. The Irish monk Fursa was also encouraged by Sigeberht. He converted many of the East Angles and was given land by the king to build a monastery, possibly at the site of Burgh Castle.

Many early religious buildings, however, were destroyed in the 9th century when East Anglia was conquered by the Danes. They defeated and killed the king, Edmund, in 869. He became a martyr and a saint and the kingdom of East Anglia vanished. Later, however, when the Danes themselves had become Christian, they built the great monastery at Bury St Edmunds dedicated to Edmund’s cult, which flourished throughout the medieval period. St Edmund remained patron saint of England until overtaken by St George at the end of the 14th century.