On the disintegration of Roman administration around 400 AD, Luguvalium seems to have survived as a town and may have been a territorial base within the British kingdom of Rheged. During this period, the first Christian missionaries were spreading the word of God throughout the land. St Ninian, St Kentigern and St Martin all have churches named after them in the area. The first Christian martyr in England was St Alban and a chapel was dedicated to this saint was in the very heart of Carlisle (unfortunately it no longer exists, but St Alban's Row survives).
St Cuthbert, the revered bishop of Lindisfarne, visited Carlisle in 685 AD and was shown what was left of the Roman buildings, including a ‘wondrous fountain'. He is thought to have founded a monastery during his visit (said to lie in the vicinity of St Cuthbert's church).