Constantine came to the throne on the death of his cousin Constantine III , whose widow, Maria , daughter of Oshin of Corycos , he married. He is usually considered one of the Lusignan dynasty.
Constantine formed an alliance with Peter I of Cyprus , offering him the port and castle of Corycus . On Peter's death in 1369, Constantine looked for a treaty with the Sultan of Egypt . The barons were unhappy with this policy, fearing annexation by the sultan, and in 1373 Constantine was murdered. Upon his death he was succeeded by his distant cousin Leo V , who would become the last king of Cilician Armenia