From Wikipedia:

"It is with Theodo that the well-sourced history of Bavaria begins. He strengthened Bavaria internally and externally, and according to Arbeo of Freising, he was a prince of great power whose fame extended beyond his borders. His father and his successors as Duke are unknown. His mother was either Appa, Gleisnot, or Gaila. In either case, his mother was a princess of Friuli.

"Theodo established his capital at Ratisbon (modern Regensburg). He married Folchaid, of the aristocracy of Alemannia, 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 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. He was the first Bavarian duke to travel to Rome, where 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.

"Two of his children are involved with the death of Saint Emmeram. Theodo's daughter Uta had become pregnant by her lover. Fearing her father's wrath, she confided to Emmeram and the saint promised bear the blame, as he was about to travel to Rome. Soon after his departure, Uta's predicament became known and in keeping with the agreement she named Emmeram as the father. Her brother Lantpert went after Emmeram and greeted him as "bishop and brother-in-law" (Aie, episcope et gener noster!) Then he had Emmeram cut and torn into pieces. Theodo had the remains of the saint moved to Regensburg. Nothing more is known of Lantpert and Uta.

"Theodo was eventually succeded by his four other sons, among which he divided his duchy sometime before 715:

* Theodbert
* Grimoald
* Theobald
* Tassilo

"As early as 702, Theodbert had been ruling from Salzburg and from 711 or 712, Theobald was co-reigning. It is impossible to see if this division was territorial (as with the Merovingians) or purely a co-regency (as with the later princes of Benevento and Capua). If so, Theodbert's capital was probably Salzburg and the Vita Corbiniani informs that Grimoald had his seat there. References to Theobald and the Thuringii implies perhaps a capital at Regensburg and this leaves Tassilo at Passau. All of this is educated conjecture."

1. Grimoald of Bavaria
2. Theodebert of Bavaria
3. TASSILO II OF BAVARIA
4. Theodoald of Bavaria

1. Author: W. H. Turton
   Title: "The Plantagenet Ancestry"
   Publication: Name: Genealogical Publishing Company, Baltimore, MD, 1968;
   Repository:
   Name: University of Georgia Library
   
   Note:
   Source Medium: Book
   
   Use with care as this book contains many errors
   
   Page: p. 8
2. Author: Charles Cawley
   Title: Foundation for Medieval Genealogy; http://fmg.ac/Projects/MedLands/index.htm
   Note:
   This database has undergone major changes and it is possible that this citation will not take you to what is now the correct location.
   Page: Bavaria, Dukes, Chapter 1