Kingdom of Essex
When they arrived in England the Saxons, like the Angles, Jutes and Frisians, were Pagans. After the Saxons gained control of Kent they set themselves up in the territory of Essex. The first attempts to convert the East Saxons to Christianity came in 604 with the arrival of Bishop (later Saint) Mellitus in London. Athelberht (King of Kent was the overlord of southern England and helped in the conversion of King Saebert of Essex.  Athelberht built and endowed St. Pauls in London, where St. Paul’s Cathedral now stands. After the death of Saebert in 616, Mellitus was driven out and the kingdom reverted to paganism. King Oswi of Northumbria convinced King Sigebert of Essex to become Christian. Sigebert then invited Chad to become Bishop of London. By 874 the Great Heathen Army held much of Essex. They established bases from which they attacked other parts of England. In 825 the kingdom of the East Saxons became part of Wessex.