When the Romans left it is clear that the economy of the area collapsed although it is now known that some people continued to live in the ruins, which became known as Kingsbury. However the centre of power moved to the Abbey, which became the centre of pilgrimage to the shrine of St Alban. The old road through the ruined city was diverted to run past the Abbey and in 948 Abbot Ulsinus had three chapels built to welcome pilgrims. One of these was St Peter's, suggesting that many pilgrims crossed the Heath on their way to the Abbey.