Marbodus, Marbod or Marbode of Rennes (c. 1035 – 11 September 1123) was archdeacon and schoolmaster at Angers, France, then Bishop of Rennes in Brittany. He was a respected poet, hagiographer, and hymnologist.
Marbod was born near Angers in Anjou, France, presumably in the mid-1030s. He received at least part of his early education at Angers under archdeacon and schoolmaster Rainaldus (d. c. 1076), who may have been trained by Fulbert of Chartres. Several of Marbod's family members were in the entourage of Count Fulk le Réchin of Anjou. Marbod was a canon in the cathedral chapter of Saint-Maurice of Angers as early as c. 1068. In about 1076 he became the cardinal archdeacon of Angers as well as the master of its cathedral school.
He was consecrated in his mid-60s as bishop of Rennes by Pope Urban II (1088–1099) during the Council of Tours (16–23 March 1096). Although Pope Urban II was a reforming pope in the tradition of Pope Gregory VII (1073–1085) (see Gregorian Reform), it is likely that Marbod's selection as bishop had a significant political component. Bishop Marbod attempted to implement reform principles in his diocese of Rennes, working to regain episcopal possessions that had been alienated by his predecessor-bishops, and helping transfer churches held by laymen to ecclesiastical hands. He was critical of the more extreme practices of Robert of Arbrissel and other such itinerant preachers wandering northwestern France at the time, but his letters indicate that he was tolerant of and even favorable towards their religious ideals.
At the age of about eighty-eight he resigned his diocese and withdrew to the Benedictine monastery of St. Aubin at Angers where he died.