Theodo's descendance has not been conclusively established. A member of the
Agilolfing dynasty, his father possibly was Duke Theodo IV of Bavaria (d. 680) and his mother was probably Fara of Bavaria (b. 600), daughter of one of the Kings of the Lombards and by her mother a granddaughter of
Gisulf I of Friuli (b. 577). Theodo established his capital at
Ratisbona (modern
Regensburg). He married Folchaid, of the Frankish (possibly
Robertian as the daughter of
Robert II) aristocracy in
Austrasia, to build diplomatic ties there. He intervened in
Lombard affairs by harbouring the refugees
Ansprand and
Liutprand, whom he assisted militarily on his return to claim the
Iron Crown. Liutprand later married his daughter Guntrude. Theodo also defended his duchy ably from the
Avars (with some failure in the east). Theodo is the patron to the four great missionaries of Bavaria:
Saint Rupert,
Saint Erhard,
Saint Emmeram, and probably
Saint Corbinian. He was the first to draw up plans for the Bavarian church, aiming both at a deeper cultivation of the countryside as well as greater independence from the
Frankish Kingdom by a closer association with the Pope. In 716, he was the first Bavarian duke to travel to
Rome, where he conferred with
Pope Gregory II. The diocesan seats were placed in the few urban centres, which served as the Duke's seats: Regensburg, Salzburg, Freising and Passau. Nothing more is known of Lantpert and Uta. ==Marriage and issue==