Saint Finan of Lindisfarne was installed and consecrated as Bishop in 651 AD. Most of his story comes from Saint Bede (Bede the Venerable) . Saint Finan was originally from Ireland and during his ten years as Bishop he was responsible for building a Cathedral dedicated to Saint Peter using hewn oak and a thatched roof in Lindisfarne. Saint Finan was a close friend of King Oswiu of Northumbria and had introduced King Sigebert (King of Essex) and King Peada (King of Middle Angles) to Christianity. Both Kings were baptized by Saint Finan in Lindisfarne.
After King Peada was baptized, Saint Finan came with him through the kingdom, preaching the Gospel and converting the Saxons living there (from the Historia ecclesiastica gentis Angolrum, Book III):
Accordingly he was baptized by Bishop Finan, with all his earls and soldiers, and their servants, that came along with him, at a noted village belonging to the king, called At the Wall. And having received four priests, who for their erudition and good life were deemed proper to instruct and baptize his nation, he returned home with much joy. These priests were Cedd and Adda, and Betti and Diuma; the last of whom was by nation a Scot, the others English. Adda was brother to Utta, ... a renowned priest, and abbot of the monastery of Gateshead. The aforesaid priests, arriving in the province with the prince, preached the word, and were willingly listened to; and many, as well of the nobility as the common sort, renouncing the abominations of idolatry, were baptized daily
Afterewards Saint Finan consecrated Diuma the Scottsman as Bishop of Anglia, Lindsey and Mercia and Saint Cedd as the Bishop of Essex. He was active at the monastery on Church Island on Lough Currane in County Kerry (now known as Saint Finan's Church). Saint Finan was buried at Lindisfarne after his death in 661 AD.