When Charles died in 1498, Andreas once again claimed the imperial titles, using them until his death. He died in poverty in Rome in 1502 and was buried in St. Peter's Basilica. In his will, he granted his titles to Ferdinand II of Aragon and Isabella I of Castile, neither of whom used them. Background The Palaiologos family was the last imperial dynasty of the Byzantine Empire and one of the empire's longest ruling dynasties, ruling the empire from 1259/1261 to its fall in 1453. By the 15th century, the Palaiologan emperors ruled a disintegrating and dwindling empire. Over the course of the 14th century, the Ottoman Turks had conquered vast swaths of territories and by the beginning of the 15th century, they ruled much of Anatolia, Bulgaria, central Greece, Serbia, Macedonia and Thessaly. The Byzantine Empire, once extending throughout the eastern Mediterranean, was more or less reduced to the imperial capital of Constantinople itself, the Peloponnese and a handful of islands in the Aegean Sea, and was forced to pay tribute to the Ottomans. As the empire dwindled, the emperors came to the conclusion that the only way to ensure that their remaining territory was kept intact was to grant some of their holdings to their sons or brothers, who received the title of despot, as appanages to defend and govern. In 1428, Andreas's father, Thomas Palaiologos, was appointed as Despot of the Morea, governing the prosperous province that constituted the parts of the Peloponnese under Byzantine control together with his older brothers Theodore and Constantine (who would later become Emperor Constantine XI, the final emperor). The brothers worked to restore Byzantine control of the entire peninsula. In 1432, Thomas brought an end to the Principality of Achaea, founded after the Fourth Crusade, by inheriting it through his marriage to Catherine Zaccaria, the daughter of Centurione II Zaccaria, the last Prince of Achaea. During Constantine's, Theodore's and Thomas's rule as despots, Byzantine rule was restored to the entire Morea, save for the scattered towns and port cities under the authority of the Republic of Venice, also holdovers from the Fourth Crusade. As their empire crumbled, the Orthodox Palaiologan emperors pursued a policy of attempting to secure military aid from Catholic Europe. Since the middle of the 14th century, the Byzantine emperors had looked to Western Europe and the papacy in the hope of securing help to save their empire