He was an important figure in Cilicia, acting as a diplomat, judge, and military officer, holding the title of Constable or Sparapet, supreme commander of the Armenian armed forces.
Other siblings included John the Bishop of Sis, Ochine of Korykos, Stephanie (later wife of King Henry I of Cyprus), and Hetoum, who became co-ruler in 1226.
[4] Historian Angus Donal Stewart, in Logic of Conquest, described it as, "The Armenian king saw alliance with the Mongols – or, more accurately, swift and peaceful subjection to them – as the best course of action.
[11][12] Sempad was a member of the Armenian supreme court, the Verin or Mec Darpas, which examined government policies and the legal codes.
He wrote the "Chronique du Royaume de Petite Arménie" (History of the Kingdom of Little Armenia) which begins around 951/952, and ends in 1274, two years before his death.
[18] He sent letters to Western rulers of Cyprus and the Principality of Antioch, describing a Central Asian realm of oasis with many Christians, generally of the Nestorian rite.
The Christians of the Orient went to the Khan of the Tartars who now rules (Güyük), and he received them with great honour and gave them freedom and let it know everywhere that no-one should dare antagonize them, be it in deeds or in words.
"One of Sempad's letters was read by Louis IX of France during his 1248 stay in Cyprus, which encouraged him to send ambassadors to the Mongols, in the person of the Dominican André de Longjumeau, who went to visit Güyük Khan.