This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
Pope Gregory the Great sent Augustine, prior of a Roman monastery, to the Kingdom of Kent, a deliberate choice of target since King Aethelberht already held influence over neighboring Anglo-Saxon kingdoms and was already married to a Christian princess from Frankish Gaul. Augustine and his companions landed on the Isle of Thanet in 597 CE, then travelled inland to reach Aethelberht's own royal seat at Canterbury.
Aethelberht received the mission and converted, granting Augustine land and freedom to preach across his kingdom, and Augustine became the first Archbishop of Canterbury, a see that has continued in that role ever since. Full conversion of the wider Anglo-Saxon kingdoms took generations rather than years to complete, and Kent itself saw a partial pagan relapse after Aethelberht's own death.
What this changed for Christianity's spread was the planting, by a papal mission chosen for exactly this political opening, of an institutional church in Anglo-Saxon England that would go on to outlast both Aethelberht's reign and the setback that followed it. Canterbury's founding under Augustine gave English Christianity a see it still answers to today, and the single converted king who made that founding possible was reason enough for Rome to have sent the mission there rather than to any other Anglo-Saxon kingdom.