Wilfrid (originally spelled Wilfrith; c. 633 – c. 709) was an English bishop and saint. Born a Northumbrian noble, he entered religious life as a teenager and studied at Lindisfarne, at Canterbury, in Gaul, and at Rome; he returned to Northumbria in about 660, and became the abbot of a newly founded monastery at Ripon. In 664 Wilfrid acted as spokesman for the Roman position at the Synod of Whitby, and became famous for his speech advocating that the Roman method for calculating the date of Easter should be adopted. His success prompted the king's son, Alhfrith, to appoint him Bishop of Northumbria. Wilfrid chose to be consecrated in Gaul because of the lack of what he considered to be validly consecrated bishops in England at that time. During Wilfrid's absence Alhfrith seems to have led an unsuccessful revolt against his father, Oswiu, leaving a question mark over Wilfrid's appointment as bishop. Before Wilfrid's return Oswiu had appointed Ceadda in his place, resulting in Wilfrid's retirement to Ripon for a few years following his arrival back in Northumbria.
After becoming Archbishop of Canterbury in 668, Theodore of Tarsus resolved the situation by deposing Ceadda and restoring Wilfrid as the Bishop of Northumbria. For the next nine years Wilfrid discharged his episcopal duties, founded monasteries, built churches, and improved the liturgy. However his diocese was very large, and Theodore wished to reform the English Church, a process which included breaking up some of the larger dioceses into smaller ones. When Wilfrid quarrelled with Ecgfrith, the Northumbrian king, Theodore took the opportunity to implement his reforms despite Wilfrid's objections. After Ecgfrith expelled him from York, Wilfrid travelled to Rome to appeal to the papacy. Pope Agatho ruled in Wilfrid's favour, but Ecgfrith refused to honour the papal decree and instead imprisoned Wilfrid on his return to Northumbria before exiling him.
Wilfrid spent the next few years in Selsey, where he founded an episcopal see and converted the pagan inhabitants of the Kingdom of Sussex to Christianity. Theodore and Wilfrid settled their differences, and Theodore urged the new Northumbrian king, Aldfrith, to allow Wilfrid's return. Aldfrith agreed to do so, but in 691 he expelled Wilfrid again. Wilfrid went to Mercia, where he helped missionaries and acted as bishop for the Mercian king.