Leo II was the tenth lord of Armenian Cilicia or “Lord of the Mountains”, and the first king of Armenian Cilicia (sometimes as Levon I the Magnificent.

During his reign, Leo succeeded in establishing Cilician Armenia as a powerful and a unified Christian state with a pre-eminence in political affairs. Leo eagerly led his kingdom alongside the armies of the Third Crusade and provided the crusaders with provisions, guides, pack animals and all manner of aid. Under his rule, Armenian power in Cilicia was at its apogee: his kingdom extended from Isauria to the Amanus Mountains.

In 1194–1195, when he was planning to receive the title of king, he instituted a union of the Armenian church with Rome. With the signing of the Act of Union, his coronation proceeded without delay. He was consecrated as king on 6 January 1198 or 1199, in the Church of Holy Wisdom at Tarsus. His accession to the throne of Cilicia as its first Armenian monarch heralded into reality not merely an official end to Cilicia's shadowy umbilical connection to the Byzantine Empire, but also a new era of ecclesiastical co-operation with the West. A skilled diplomat and wise politician, Leo established useful alliances with many of the contemporary rulers; he also gained the friendship and support of the Hospitallers and the Teutonic Knights by granting considerable territories to them.

He envisioned annexing the Principality of Antioch to his kingdom, thus reinforcing his authority along much of the northeastern Mediterranean coastline. Levon first put this plan into action in 1194 by seizing the strategic fortress of Baghras after Saladin, the Sultan of Egypt and Syria, had abandoned it. His greatest triumph was achieved at the beginning of 1216 when at the head of his army he occupied Antioch and installed his grandnephew, Raymond-Roupen as its head. Raymond-Roupen remained in power until Leo's death. The transforming of the Armenian court, following the pattern of the Frankish courts, proceeded at a more rapid pace after Leo came to power. Many of the old names of specific functions or the titles of dignitaries were replaced by Latin ones and the changes in nomenclature were often accompanied by changes in the character of these offices.

Commerce was greatly developed during the reign of Leo: he granted charters regarding trade and commercial privileges to Genoa, Venice and Pisa. These charters provided their holders with special tax exemptions in exchange for their merchandising trade. They encouraged the establishment of Italian merchant communities in Tarsus, Adana and Mamistra, and became a large source of revenue for the growth and development of Cilician Armenia.

He was the younger son of Stephen, the third son of Leo I, lord of Armenian Cilicia. His mother was Rita, a daughter of Sempad, Lord of Barbaron. Leo's father, who was on his way to attend a banquet given by the Byzantine governor of Cilicia, Andronicus Euphorbenus, was murdered on 7 February 1165. Following their father's death, Leo and his elder brother Roupen lived with their maternal uncle, Pagouran, lord of the fortress of Barbaron, protecting the Cilician Gates pass in the Taurus Mountains.

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. The seigneurs of Cilician Armenia elected Leo's brother, Roupen III to occupy the throne of the principality. In 1183, Hethum III of Lampron, allied with Prince Bohemond III of Antioch, began joint hostilities against Roupen III who sent Leo to surround Hethum's mountain lair. But Bohemond III, rushing to the aid of Hethum, treacherously made Roupen prisoner.

His brother's absence gave Leo the opportunity to put his sharp political skills to practice as the interim guardian of the Roupenian House. Roupen's release required payment of a large ransom, and the submission of Adana and Mamistra as vassalages to Antioch. When Roupen returned from the captivity, he transferred the power to his brother, Leo (1187) and retired to the monastery of Trazarg.

Prince of Cilicia

The menace of the recent alliance between the Byzantine Emperor Isaac II Angelos and Saladin, and the more immediate threat of the Turkomans, led to a rapprochement between Leo and Bohemond III: on his accession Leo sought an alliance with the prince of Antioch and recognized his suzerainty. Large bands of the nomad Turkomans had been crossing the northern borders, advancing almost as far as Sis and laying waste on all sides; the two princes joined to beat off a Turcoman raid in 1187. Leo could muster only a small force, but he attacked them with such energy that he routed the bands, killed their leader, and pursued the fugitives as far as Sarventikar, inflicting heavy losses on them. Soon afterwards (between 3 February 1188/4 February 1189), Leo married Isabella, a niece of Bohemond III's wife Sibylla.

The following year (1188), taking advantage of the troubled condition in the Sultanate of Rûm that preceded the death of Kilij Arslan II, Leo turned against the Seljuks.A surprise attack on Bragana was unsuccessful, but Leon returned two months later with a larger army, killed the head of the garrison, seized the fortress and marched into Isauria. Though we find no specific mention of it, Seleucia must have been captured about this time. Proceeding northwards, Leo seized Heraclea, gave it up after payment to him a large sum, and advanced as far as Caesarea.

Leo was a valiant and learned prince; he enlarged his principality and became the master of many provinces. A few days only after his taking possession of the country, the descendants of Ismael, under the command of one Roustam, advanced and came against Cilicia. Leo was not frightened, but confiding in God, who destroyed Sanacherib, he vanquished with a few men the great army of the infidels. Roustam himself being killed by St. George, the whole Hagarenian army then fled and dispersed; the Armenians pursued them and enriched themselves by the booty. 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.