General Michael Melissenos

the family stretches back another half-century to the general Michael Melissenos, a favourite of Emperor Constantine V (r. 741–775). This Michael married a sister of Constantine's wife, Eudokia, and their son, Theodore Kassiteras Melissenos, became Patriarch of Constantinople in 815–821.

https://en.wikipedia.org/wiki/Michael_Melissenos?wprov=sfla1