Ruben I, (; 1025âÂÂ1095) was the first lord of Armenian Cilicia from 1080 until his death.
The first movement of Armenian nobles immigrating to the Byzantine Empire began during the reign of Emperor Maurice, when Armenians voluntarily joined the Byzantine army. Mass Armenian immigration began when the Seljuks raided the Aras River, leaving the areas around Lake Van unprotected. In the 10th century, a large number of Armenian settlers settled in Cilicia.
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. The plateaus around the Taurus Mountains were very difficult to access, which allowed Ruben to easily organize a band of Armenian troops to revolt against the Byzantine Empire.
In 1079 Ruben's troops advanced south to Kozan and captured the city from the Empire. In 1080, the foundation of the independent Armenian princedom of Cilicia, and the future kingdom, was laid by many other Armenian lords and nobles united under Ruben's leadership. 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.
He was 70 when he died, buried at the monastery of Castalon.
The name of RoupenâÂÂs wife is unknown. His recorded children are: