A monastery near Braga province of Gallaecia. Its presence dates from shortly after 550, the date of the arrival in those lands of its founder and first abbot St. Martin of Dumium or Braga, at the same time as the conversion of the Suevi to Catholicism. In 556, in order to have St. Martin as bishop, it was raised to an episcopal see; from then on its abbots were all bishops. The monastery was always a suffragan see of Braga. It had a rich library. Among its monks we know Paschasius, whom St. Martin charged with translating the Vitae Patrum PL 73, 1025-1062. The Dumium episcopate coexisted with that of Braga until the time of the Arab invasion, although sometimes the two dioceses had the same man as bishop, as the lists of prelates show.