The Byzantine chronicle of Scylitzes Continuatus states that "the emperor had given his niece the Synadene, daughter of Theodoulos Synadenos, to the krales of Hungary for a wife; upon his death she returned to Byzantium."
[1] An important clue to the identity of Synadene's husband lies in one of the enamel plaques contained in the Holy Crown of Hungary, which depicts a man identified as "Géza, faithful king of the Hungarians".
Géza I's death on 25 April 1077 corresponds to Scylitzes Continuatus's narration, with the queen dowager returning to the Byzantine Empire by late 1079.
He referred to the union as a "private arrangement" between Duke Géza and those Byzantine commanders (including Synadene's uncle, who had not yet become emperor) who were in charge of Balkan and Danubian territories.
Géza then possibly ruled south-eastern part of Hungary, on the border of the Byzantine Empire, and had a poor relationship with his cousin, King Solomon, making the marriage with Synadene politically advantageous.