One of the princes who came after Philaretos' invitation was Ruben, who had close ties with the last Bagratid Armenian king, Gagik II. Ruben was alongside the Armenian ruler Gagik when he went to Constantinople upon the Byzantine emperor's request. Instead of negotiating peace, however, the king was forced to cede his Armenian lands and live in exile. Gagik was later assassinated by Greeks. In 1080, soon after this assassination, Ruben organized a band of Armenian troops and revolted against the Byzantine Empire. He was joined by many other Armenian lords and nobles. Thus, in 1080, the foundations of the independent Armenian princedom of Cilicia, and the future kingdom, were laid under Ruben's leadership. He began leading bold and successful military campaigns against the Byzantines, and on one occasion he culminated his venture with the capture of the fortress of Pardzerpert which became a stronghold of the Roupenian dynasty.