Question: What nationality is John Doukas (Sebastokrator)'s father?
Sentence (from "John Doukas (sebastokrator)"): John Doukas, Latinized as Ducas, ("Iōannēs Doukas"; –) was the eldest son of Constantine Angelos by Theodora Komnene, the seventh child of the Byzantine Emperor Alexios I Komnenos and Irene Doukaina, from whose family name John Doukas took his own.
Relevant evidence: Yes