[10] Leo's father, who was on his way to attend a banquet given by the Byzantine governor of Cilicia, Andronicus Euphorbenus,[4] was murdered[7]: [page needed]  on 7 February 1165.

[4][11] Their paternal uncle, Mleh I, lord of Armenian Cilicia had made a host of enemies by his cruelties in his country, resulting in his assassination by his own soldiers in the city of Sis in 1175.

Roustam himself was killed by St. George, the whole Hagarenian army then fled and dispersed; the Armenians pursued them and enriched themselves with the treasure.

The power of Leo thus increased, and being confident in his strength, he chased the Tadjiks [name used by Armenian chroniclers to designate the Saracens, particularly the Seljuks] and pursued the Turks; he conquered Isauria and came as far as Iconium; he captured Heraclea, and again gave it up for a large ransom; he blockaded Caesarea, and had nearly taken it; he made a treaty with the Sultan of Iconium, and received a large sum of money from him; he surrounded Cilicia on every side with forts and castles; he built a new church called Agner, and was exceedingly generous to all monasteries erected by his ancestors; his bounty extended itself even to the leprous; they being shunned by everybody and expelled from every place, he assigned to them a particular house, and provided them with necessaries.

He was a wise, brilliant man, a skilled horseman, brave-hearted in battle, with attention to human and divine charity, energetic and happy of countenance.