 Despite being counted as one of the 28 cities of Sub @-@ Roman Britain , it seems that after the Romans left Britain in 410 Durovernum Cantiacorum was abandoned except by a few farmers and gradually decayed . Over the next 100 years , an Anglo @-@ Saxon community formed within the city walls , as Jutish refugees arrived , possibly intermarrying with the locals . In 597 , Pope Gregory the Great sent Augustine to convert its King Æthelberht to Christianity . After the conversion , Canterbury , being a Roman town , was chosen by Augustine as the centre for his episcopal see in Kent , and an abbey and cathedral were built . Augustine thus became the first Archbishop of Canterbury . The town 's new importance led to its revival , and trades developed in pottery , textiles , and leather . By 630 , gold coins were being struck at the Canterbury mint . In 672 , the Synod of Hertford gave the see of Canterbury authority over the entire English Church . 
