After the Romans withdrew from Britain in the fifth century, the Anglo-Saxons began their invasion.

Eventually York would become Eoferwic and, under the rule of Edwin, King of Northumbria, it became an important religious centre. In fact, Edwin was instrumental in re-introducing Christianity to the city and was baptised at Eoferwic.

Edwin married the Christian Princess Ethelberga of Kent who came north with her Chaplain, Bishop Paulinus. He baptised Edwin and many of his subjects on April 12 627, at one of the city's wells where a little wooden church had been built for them to worship in. This was the first cathedral of St Peter in York, with Paulinus as its first Bishop in the present continuous line.

Christianity also brought learning to York. In the eighth century, the great scholar Alcuin was Master of the School of St Peter which received students from all over Europe. By the time he left Britain to become Master of Emperor Charlemagne's Palace School at Aachen, Eoferwic was the most important centre of learning in this part of Britain.