Ruben was a descendant of the
Bagratids. He went alongside the Armenian king
Gagik II to
Constantinople to sign an allegedly permanent peace-treaty upon the Byzantine emperor
Constantine IX's request. However, Gagik was forced by the emperor to hand over his Armenian territory and live in exile. Gagik was later assassinated by the Byzantine governors of
Kyzistra. After Gagik II was killed, his relatives and followers fled to the
Taurus Mountains and found refuge in the castle of Kapitar, north of
Kozan. In 1079 Ruben's troops advanced south to Kozan and captured the city from the Empire. Through continuous military campaigns against the Byzantines, he managed to expand his territory to the entire plain of
Cilicia, in one of which he captured the powerful Castle of Antirim and made it a military base for his family. His descendants are called
Rubenids. File:The Barony of Cilician Armenia, 1080-1199.gif|Rubenid initial territory marked in red File:Drapeau roupénide.png|Coat of arms of the Rubenids == Death ==