At this date, Athelm (later Archbishop of Canterbury) was appointed the first bishop of the Diocese of Wells, making the secular church there into the diocesan cathedral.

Under him, grants of land were obtained successively from the kings Edward the Confessor, Harold and William the Conqueror and buildings were constructed for the secular community.

As well as rebuilding the cathedral he instituted the arrangement by which although Bath retained precedence, the seat was located in both churches and the bishop was elected by both chapters.

He moved his seat there, with the approval of Pope Celestine III, and the see became officially known as the Diocese of Glastonbury.

Although he did not use the name of Wells in his title, his contribution to the city was greater than any other bishop of the diocese: under his authority the cathedral was restored and enlarged, adding the west front, making this the visual signature of the building.

Following his death in 1242 however, the monks at Bath unilaterally elected one of their number, Roger, as successor, in disregard for the chapter of Wells.

William of Bitton bishop from 1267 to 1274 was renowned for his piety, and his tomb became a place of pilgrimage in Wells.

He was succeeded by Adriano Castellesi (1504–18) who was an absentee bishop, under whom the see was administered by Polydore Vergil the noted historian.

The Report of the Commissioners appointed by his Majesty to inquire into the Ecclesiastical Revenues of England and Wales (1835) found the see had an annual net income of £5,946.