Aidan Hart: St. Theodore. He was an Eastern monk, not even a priest, whom the Pope made a surprise choice for Canterbury right after the Synod of Whitby, with its conflicts between Romanism and Celtic Christianity. (Rome won.) There was deep division to heal, as well as new liturgical forms to introduce. He managed to unite the English Church and to improve its administration, drawing diocesan and parochial boundaries that remain largely intact today. He was an old man, 66, when he became archbishop, and continued to serve until his death at 88. He also helped unify the Celtic and Roman strains in English Christianity, becoming, as Bede wrote, the first Archbishop everyone obeyed.