Robert's marriage contract and is recorded as having labored intensely to free Robert when he at one point was imprisoned in the Kingdom of Hungary. One factor that might have contributed to Leonardo I's rise to power was his marriage to Maddalena de' Buondelmonti, the niece of Niccolò Acciaioli, Grand Seneschal of the Kingdom of Naples. In 1362, Leonardo I seized the nearby island Lefkada and the fortress of Vonitsa, located on the mainland. He assumed the additional titles "Lord of Vonitsa" and Dux Leucade ("Duke of Lefkada"). The taking of Lefkada and Vonitsa were not outright conquests; the locals had grown dissatisfied by their ruling family, the Venetian Zorzi, and had summoned Leonardo I to their aid. Although contemporary chroniclers wrote that Leonardo promised to respect the local Orthodox religion, he is also recorded to have driven the local Orthodox archbishop from Vonitsa. Upon Leonardo I's death in the 1370s, his domain was inherited by his infant son, Carlo I Tocco, with the administration of his early reign handled by his mother Maddalena as regent. By the late 1380s, Carlo I was, according to the historian William Miller, the most powerful remaining Latin ruler in the eastern Mediterranean. Around 1390, Carlo reached maturity and his mother's regency ended. He married Francesca Acciaioli, daughter of Nerio I Acciaioli, Duke of Athens (1285/1394–1394). Carlo I's most trusted advisor and military leader was his younger brother, Leonardo II Tocco, who as a reward for his services was granted the island of Zakynthos in 1399. The island was not given away as a usual feudal possession, since it was specified that regardless of Leonardo II fathering any children, the island would be returned to Carlo I at the time of his death. In 1394, Carlo I came into conflict with Theodore I Palaiologos, son of Emperor John V Palaiologos and Despot of the Morea (1383–1407). Nerio I of Athens died in September 1394 and designated Carlo I's wife Francesca as the heir to all his possessions and as the guardian of the town of Corinth. The will almost completely disregarded Francesca's older sister, Bartolomea Acciaioli, wife of Theodore I Palaiologos. As a result, Theodore attacked Corinth almost immediately after Nerio's death, claiming the right by primogeniture rather than following the will. Francesca held power in the town as she had been present there at the time of Nerio's death, and actively participated in