FMG finds no relationships for THEODERIC (-after 743). http://fmg.ac/Projects/MedLands/SAXONY.htm See below.
I'm removing his present relationships and locking them.
Chapter 1. EARLY SAXON LEADERS, family of WIDUKIND
The relationship between the following individual Saxon chiefs and small family groups cannot be established. However, the repeated use of names, in particular Theoderich and Widukind, over the course of two centuries suggests a close family connection, although this may have been through either the male or female line. As noted in the Introduction to the present document, the family of Widukind constituted one of the three main power sources in Saxony until well into the 11th century.
1. HADUGATO (-after [531]). Adam of Bremen names "Hadugato" as the duke of the Saxons to whom "Theodericus rex Francorum" sent legates[11], undated but recorded immediately after the Thuringian invasion of Theoderic I King of the Franks which is dated to 531.
1. THEODERIC (-after 743). Einhard records that "Karlomannus" was in Saxony at "castrum Hohseoburg" and there accepted the surrender of "Theodericum Saxonem illius loci primarium" in 743[12]. Theoderic was captured again in 744 when Carloman invaded Saxony with his brother Pepin[13]. Pepin King of the Franks invaded Saxony once more in 758, captured Sythen and required an annual tribute of 300 horses from the Saxons[14].
2. WIDUKIND (-7 Jan 810). The Royal Frankish Annals record that Widukind rebelled against the authority of Charles I King of the Franks, who had invaded and subdued Saxony, and fled to Denmark ["Nordmannia"] in 777[15].
