Gregory of Utrecht was born of a noble family at Trier. He became a follower of Saint Boniface, who sent him to study at the Monastery of Saint Michael at Ohrdruf. He then accompanied Boniface on his missionary journeys. In 750, Boniface appointed Gregory abbot of St. Martin's Monastery in Utrecht. St. Martin's became a centre of learning and missionary activity. When, in 754, Eoban left to accompany Boniface on their last missionary trip, Gregory was tasked with administering the diocese of Utrecht, which he did faithfully for the next twenty-three years until his death in 776.