From his life, written by Altfrid, one of his successors, and another
compiled by a monk of Werden, about sixty years after the death of St.
Ludger, of inferior authority to the former, both extant in Mabillon,
Act. Bened. t. 4, p. 489: also a third life in Surius and the
Bollandists, written by the monks of Werden perhaps twenty years after
the latter. See Hist. Litter. Fr. t. 5, p. 660.