Antigonus I Monophthalmus
Through his maternal grandmother Antonia Tryphaena, he was a descendant of Roman triumvir Mark Antony. Tryphaena was the first great granddaughter born to the triumvir. Through Tryphaena, Cotys I was also related to various members of the Julio-Claudian dynasty. Through Aspurgus, Cotys I was a descendant of the Greek Macedonian Kings: Antigonus I Monophthalmus, Seleucus I Nicator and Regent, Antipater. These three men served under King Alexander the Great. Cotys I was named in honor of his late maternal grandfather, Roman client ruler of Thrace Cotys VIII.