Saint Gerald was an English monk and later the bishop of Mayo. His exact birthdate is unknown, but history records that after the Synod of Whitby in 664, he left England and followed Saint Colman to Ireland. In 668, they settled in Innisboffin.
After some time, disagreements arose between the Irish monks and the English monks living there. To resolve this, Saint Colman established a separate monastery for the thirty English monks. This became known as the Abbey of Mayo, often called Mayo of the Saxons. In 670, Saint Gerald became its first abbot.
The Venerable Bede later wrote that by the year 731, the monastery was still occupied by English monks who lived a disciplined and simple life. They supported themselves by manual work, followed a monastic rule and a canonical abbot, and lived in purity and dedication.
Although still young when appointed, Saint Gerald proved to be a wise and capable leader. He governed the Abbey until 697, when tradition says he resigned and allowed Saint Adamnan to take charge. Some accounts mention that Saint Adamnan celebrated the Roman Easter in Mayo in 703 before travelling to Skreen in Hy Fiachrach. After his departure, the monks asked Saint Gerald to return as abbot.
Mayo was later joined with Tuam for a time, but it remained a separate diocese until 1579.
Saint Gerald continued to lead the Abbey and Diocese of Mayo until his death on March 13, 731. His feast is celebrated on December 5.