[1] Thamar was the daughter of Nikephoros I Komnenos Doukas of the Despotate of Epirus and his second wife Anna Palaiologina Kantakouzene, niece of the Byzantine Emperor Michael VIII Palaiologos.

To reunite Epirus with the Empire, Anna wanted to marry Thamar to Michael, the son and co-emperor of Andronikos II Palaiologos.

With the failure of Anna’s plan, Thamar's father Nikephoros attempted to strengthen his independence from Constantinople by allying himself with the Angevin dynasty of Naples.

Philip suspected his wife of acting in her family's interests over his during the two-year conflict that raged between the Angevins and Epirus, despite the fact that she had pawned the remainder of her jewellery to help him pay for the military effort.

She was forced into confessing that she had slept with at least forty of the lords of his court and that she had formed a particular relationship with Bartolomeo Siginulfo, the Grand Chamberlain of Taranto.