The 7th century saw the conversion of Essex (including Thurrock) from Paganism to Christianity, but it took three attempts. At the beginning of the 7th century, London was part of the Kingdom of the East Saxons – the people, not the geographic area. King Saebert converted to Christianity at the behest of his overlord, King Æthelberht of Kent. Saint Mellitus became Bishop of London and his see included Essex. Essex reverted to Paganism on the death of King Saebert and Mellitus was forced to leave.
Around AD 655, St Cedd undertook a successful mission to re-convert the East Saxons and built churches at Bradwell and Tilbury. The building of the Tilbury church (on the banks of the Thames) was described in Bede’s History of the English Church and is the earliest written reference to a location in Thurrock. St Cedd became Bishop of the East Saxons, in effect, Bishop of London. He died on 26th October, AD 664. However, on the death of King Sigeberht II (the Good), Essex again reverted to Paganism.
West Tilbury church, possibly on the site of St Cedd’s church.
The final (and lasting) conversion of the East Saxons to Christianity took place following a mission by Bishop Jaruman of Lichfield sent by King Wulfhere of Mercia, who was overlord of the East Saxons.