Joan was possibly born in about 1297, and was the eldest daughter of five children, having had two older brothers, Charles and Philip, and two younger sisters, Margaret, who married Walter VI of Brienne and Blanche, who married Ramon Berenguer of Aragon. Joan's parents did not have a good relationship: Philip suspected Thamar of acting in her family's interests over his during the two-year conflict that raged between the Capetian House of Anjou and Epirus, despite the fact that she had pawned the remainder of her jewellery to help him pay for the military effort. Distrustful of Thamar, Philip decided to divorce her and in 1309accused her of having committed adultery. She was forced into confessing that she had had sexual relationships 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. Thamar became an outcast, probably never seeing her children again, she either became a nun or was imprisoned by Philip. In either case she died not long afterwards in 1311. Shortly following her mother's death, Joan acquired a stepmother in Catherine of Valois, who Philip married in July 1313. From this marriage Joan acquired five half-siblings, including Philip II, Prince of Taranto.
In February 1316, Joan married her first husband, Oshin, King of Armenia. Joan was Oshin's third wife, from his first marriage he had had a son Leo. From this marriage she adopted the name Eirene. The couple were only married for four years. On his death on July 20, 1320, Oshin was succeeded by his minor son Leo. It was believed that Oshin was poisoned Soon after Oshin's death, his cousin Oshin of Korikos became regent. He wished to make himself and his family more secure in Armenia. Steps were taken to make this happen; Oshin married Joan, who was forced into the marriage. Oshin married his daughter Alice off to Joan's stepson Leo. Oshin was also probably responsible for the deaths of King Oshin's sister Isabella and two of her sons, in order to remove rival claimants. Joan died in March 1323, she was outlived by her ill-fated second husband. Six years after Joan's death, Leo reached majority, he took revenge on his regent. Joan's husband and brother-in-law Constantine, Constable of Armenia and Lord of Lampron, and Leo's wife Alice were all murdered on the king's orders, the head of Oshin being sent to the Ilkhan and of Constantine to Al-Nasr Muhammad.
