Nicholas Orsini (; ) was a Greek–Italian nobleman who was count palatine of Cephalonia from 1317 to 1323 and ruler of southern Epirus around Arta from 1318 to 1323. The son of Count John I Orsini and an Epirote princess, he succeeded his father upon the latter's death, and in the next year murdered his uncle, Thomas Komnenos Doukas, and usurped his rule of Epirus. While able to secure his control over southern Epirus, however, the north with the city of Ioannina were taken over by the Byzantine Empire. Nicholas' attempts to ally with the Republic of Venice and recover Ioannina failed, and he was in turn killed by his brother John II Orsini in 1323. Life Nicholas was the son of Count John I Orsini of Cephalonia by Maria, a daughter of Nikephoros I Komnenos Doukas of Epirus by Anna Palaiologina Kantakouzene. His father governed Cephalonia as a vassal of King Charles II of Naples, and had acquired Leukas as his wife's dowry. John had a close relationship with his father-in-law, and with his wife lived at the Epirote court at Arta until 1303, when John succeeded his father, Richard Orsini. John nevertheless joined in attacks on Epirus ordered by his Angevin suzerains, King Charles II of Naples and Philip of Taranto in 1304 and 1306. John appears to have played a part in instigating these attacks, apparently aiming to become the new ruler of Epirus. Nicholas succeeded to the county on his father's death in 1317, and like his father also set his sights on Epirus. In 1318 he surprised and murdered his childless uncle, Thomas I Komnenos Doukas of Epirus, and easily subdued the entire southern portion of the principality around Arta. To solidify his position among the local population, Nicholas espoused Eastern Orthodoxy, used the Greek language, and married his uncle's widow, Anna Palaiologina, daughter of the Byzantine co-emperor Michael IX Palaiologos and granddaughter of Emperor Andronikos II Palaiologos. Although Anna was his aunt, the Church appears to have acquiesced to their marriage. The historian Donald Nicol suggests that Anna may have been involved in Thomas' murder, as he had mistreated her. The Angevins did not entirely welcome Nicholas' actions, as they clashed with their own claims over Epirus. While Nicholas had sworn allegiance to the new Prince of Achaea, John of Gravina in 1318 as the latter's feudal vassal, in the next year, when prompted