Cotys was raised and educated in Rome along with his distant relative the future Roman Emperor Caligula.
Her circle assisted in the political preservation of the Roman Empire's borders and affairs of the client states.
In 38 Rhoemetalces III became Roman Client King of Thrace and had married Cotys’ sister Pythodoris II.
Sometime after 48, Roman Emperor Claudius requested Cotys to abdicate the throne and replaced him with a former Armenian King, Mithridates of Armenia.
At first Cotys successfully resisted Claudius’ request, with the support of Roman and local Armenian nobles.