Leo was born in 1236, the son of King Hetoum I and Queen Isabella. Hetoum and Isabella's marriage in 1226 had been a forced one by Hetoum's father Constantine of Baberon, who had arranged for Queen Isabella's first husband to be murdered so as to put Constantine's own son Hetoum in place as a co-ruler with Isabella. They had six children, of which Leo was the eldest. One of his sisters was Sibylla of Armenia, who was married to Bohemond VI of Antioch to bring peace between Armenia and Antioch. In 1262 Leo married Keran, the daughter of Prince Hetoum of Lampron. In 1266, while their father king Hetoum I was away to visit the Mongol court, Leo and his younger brother Thoros fought to repel Mamluk invaders, at the Battle of Mari. Thoros was killed in combat, and Leo, along with 40,000 other Armenian soldiers was captured and imprisoned. When King Hetoum returned, he paid a large ransom to retrieve his son, including a large quantity of money, handing over several fortresses, and accepting to intercede with the Mongol ruler Abagha in order to have one of Baibars's relatives freed.
Reign
Hetoum I abdicated in 1269 in favour of his son, and entered the Franciscan order. He died a year later. The new king Leo II was known as a pious king, devoted to Christianity. He pursued active commercial relations with the West, by renewing trade agreements with the Italians and establishing new ones with the Catalans. He also endeavoured to reinforce the Mongol alliance, as his father Hetoum I had submitted Armenia to Mongol authority in 1247. In 1271, Marco Polo visited the Armenian harbour of Ayas and commented favourably about Leo's reign and the abundance of the country, although he mentions his military forces were rather demoralized: in 1281. In 1275 the Mamluk sultan Baibars invaded Cilicia for a second time. The following year, Armenia fought off an invasion by the Turkomans, but the Constable Sempad, Leo's uncle, was killed in combat.
Mongol alliance
In 1281 Leo joined the Mongols in their invasion of Syria, but they were vanquished at the Second Battle of Homs. Leo had to sue for peace, and in 1285 obtained a 10-year truce in exchange for important territorial concessions in favour of the Mamluks. Leo died in 1289 from arsenic, and was succeeded by his son Hetoum II.
Descendance
During twenty-one years of marriage Leo had sixteen children by his wife Keran, ten sons and six daughters. Five of his children reached the throne. The eldest, Hetoum II of Armenia, abdicated after four years in favor of his younger brother Thoros III of Armenia, but was placed back on the throne in 1294. In 1296, their brother Sempad of Armenia blinded Hetoum and in 1298 he strangled Thoros, in order to seize power. Sempad was then overthrown in 1298 by their younger brother Constantine III of Armenia, who was replaced by older brother Hetoum, who then abdicated in 1305 in favor of Thoros's son Leo III of Armenia.
