Thomas Palaiologos (; 1409 – 12 May 1465) was Despot of the Morea from 1428 until the fall of the despotate in 1460, although he continued to claim the title until his death five years later. He was the younger brother of Constantine XI Palaiologos, the final Byzantine emperor. Thomas was appointed as Despot of the Morea by his oldest brother, Emperor John VIII Palaiologos, in 1428, joining his two brothers and other despots Theodore and Constantine, already governing the Morea. Though Theodore proved reluctant to cooperate with his brothers, Thomas and Constantine successfully worked to strengthen the despotate and expand its borders. In 1432, Thomas brought the remaining territories of the Latin Principality of Achaea, established during the Fourth Crusade more than two hundred years earlier, into Byzantine hands by marrying Catherine Zaccaria, heiress to the principality.
In 1449, Thomas supported the ascension of his brother Constantine, who then became Emperor Constantine XI, to the throne despite the machinations of his other brother, Demetrios, who himself desired the throne. After Constantine's rise to the throne, Demetrios was then assigned by Constantine to govern the Morea with Thomas but the two brothers found it difficult to cooperate, often quarreling with each other. In the aftermath of the Fall of Constantinople and end of the Byzantine Empire in 1453, Ottoman Sultan Mehmed II allowed Thomas and Demetrios to continue to rule as Ottoman vassals in the Morea. Thomas hoped to turn the small despotate into a rallying point of a campaign to restore the empire, hoping to gain support from the Papacy and Western Europe. Constant quarreling with Demetrios, who supported the Ottomans instead, eventually led Mehmed to invade and conquer the Morea in 1460.
Thomas and his family, including his wife Catherine and his three younger children Zoe, Andreas and Manuel, escaped into exile to the Venetian-held city of Methoni and then to Corfu, where Catherine and the children stayed. In the hopes of raising support for a crusade to restore his lands in the Morea, and possibly the Byzantine Empire itself, Thomas travelled to Rome, where he was received and provided for by Pope Pius II. His hopes of retaking the Morea never materialized and he died in Rome on 12 May 1465. After his death, his claims were inherited by his oldest son Andreas, who also attempted to rally support for a campaign to restore the fallen despotate and the Byzantine Empire.
Biography
Early life and appointment as despot
As the Byzantine Empire fell apart and fragmented over the course of the 14th century, the emperors of the Palaiologan dynasty came to feel that the only sure way to keep their remaining holdings intact was to grant them to their sons, receiving the title of despot, as appanages to defend and govern. Emperor Manuel II Palaiologos (1391–1425) had a total of six sons who survived infancy. Manuel's eldest surviving son, John, was raised to co-emperor and designated to succeed Manuel as sole emperor upon his death. The second eldest son, Theodore was designated as Despot of the Morea and the third eldest, Andronikos, was made Despot of Thessaloniki in 1408 at just eight years old. Manuel's younger sons, Constantine, Demetrios, and Thomas (the youngest, born in 1409), were kept in Constantinople as there was not sufficient land left to grant them. The younger children; Theodore, Andronikos, Constantine, Demetrios and Thomas were frequently described as having the distinction of Porphyrogennetos ("born in the purple"; born in the imperial palace during the reign of their father), a distinction that does not appear to have been shared by the emperor-to-be John.
Relations between the Palaiologos brothers were not always good. Though the young John and Constantine appears to have got on well with each other, relations between Constantine and the younger Demetrios and Thomas were not as friendly. The complex relationships between the sons of Manuel II were put to the test when John, now Emperor John VIII, appointed Constantine as Despot of the Morea in 1428. Since his brother Theodore refused to step down from his role as despot, the despotate became governed by two members of the imperial family for the first time since its creation in 1349. Soon thereafter, the younger Thomas (aged 19) was also appointed as Despot of the Morea, meaning that the nominally undivided despotate had effectively disintegrated into three smaller principalities.
Theodore did not make way for Constantine or Thomas in the despotate's capital, Mystras. Instead, Theodore granted Constantine lands throughout the Morea, including the northern harbor town of Aigio, fortresses and towns in Laconia (in the south), and Kalamata and Messenia in the west. Constantine made his capital as despot the town Glarentza. Meanwhile, Thomas was given lands in the north and based himself in the castle of Kalavryta.
Despot under the Byzantine Empire
Strengthening the Morea
Shortly after being appointed as despots, Constantine and Thomas, together with Theodore, decided to join forces in an attempt to seize the flourishing and strategic port of Patras in the north-west of the Morea, then under the rule of its Catholic Archbishop. The campaign, which was unsuccessful, possibly due to Theodore's reluctance to partake, was Thomas's first experience of war. Constantine later captured Patras on his own, ending 225 years of foreign ownership.
Thomas's early tenure as Despot of the Morea was not without acquisitions either. For years, Thomas and Constantine had been eating away at the last remnants of the Principality of Achaea, a crusader state established during the Fourth Crusade in 1204 which had once governed almost the entire peninsula. It was Thomas who finally brought an end to the principality by marrying Catherine Zaccaria, daughter and heir of the final prince, Centurione II Zaccaria. With Centurione's death in 1432, Thomas could claim control over all of his remaining territories. By the 1430s, Thomas and Constantine had ensured that nearly the entire Peloponnese was once more in Byzantine hands for the first time since 1204, the only exception being the few port towns and cities held by the Republic of Venice.
Murad II, Sultan of the Ottoman Empire, which occupied most of the Byzantine Empire's former territory and had relegated the empire and the despotate as effectively vassal states, felt uneasy about the recent string of Byzantine successes in the Morea. In 1431, Turahan Bey, a Turkish general who governed Thessaly, sent his troops south to demolish the Morea's primary defensive fortifications, the Hexamilion wall, in an effort to remind the despots that they were the Sultan's vassals.
In March 1432, Constantine, possibly desiring to be closer to Mystras, made a new territorial agreement, presumably approved by Theodore and John VIII, with Thomas. Thomas agreed to cede his fortress Kalavryta to Constantine, who made it his new capital, in exchange for Elis, which Thomas made his new capital. Though relations between the three despots thus appears to have been good in 1432, they soon soured. John VIII had no sons to succeed him and it was thus assumed that his successor would be one of his four surviving brothers (Andronikos having died some time before). John VIII's preferred successor was Constantine and though this choice was accepted by Thomas, who had developed good relations with his older brother, it was resented by the still older Theodore. When Constantine was summoned to the capital in 1435, Theodore believed this was to appoint Constantine as co-emperor and designated heir, which was not actually the case, and he too travelled to Constantinople to raise his objections. The quarrel between Constantine and Theodore was not resolved until the end of 1436, when the future Patriarch Gregory Mammas was sent to reconcile them and prevent civil war. When Constantine was summoned to act as regent in Constantinople while John VIII was away at the Council of Florence from 1437 to 1440, Theodore and Thomas stayed in the Morea. In November 1443, Constantine gave over control of Selymbria, which he had received after helping to deal with the rebellion of their younger brother Demetrios, to Theodore, who in turn abandoned his position as Despot of the Morea, making Constantine and Thomas the sole Despots of the Morea. Though this brought Theodore closer to Constantinople, it also made Constantine the ruler of the capital of the Morea and one of the most powerful men in the small empire. With Theodore and Demetrios out of their way, Constantine and Thomas hoped to strengthen the Morea, by now the cultural center of the Byzantine world, and make it a safe and nearly self-sufficient principality. The philosopher Gemistus Pletho advocated that while Constantinople was the New Rome, Mystras and the Morea could become the "New Sparta", a centralized and strong Hellenic kingdom in its own right.
Turkish attacks and the accession of Constantine XI
Among the actions taken during the brothers' project of strengthening the despotate was to reconstruct the Hexamilion wall, destroyed by the Turks in 1431. Together, they completely restored the wall, which was finished in March 1444. The wall was destroyed by the Turks again in 1446 after Constantine had attempted to expand his control northwards and had refused the sultan's demands of dismantling the wall. Constantine and Thomas were determined to hold the wall and had brought all their available forces, amounting to perhaps as many as twenty thousand men, to defend it. Despite this, the battle by the wall in 1446 was an overwhelming Turkish victory, with Constantine and Thomas barely escaping with their lives. Turahan Bey was sent south to take Mystras and devastate Constantine's lands while Sultan Murad II led his forces in the north of the Peloponnese. Although Turahan failed to take Mystras, this was of little consequence as Murad did not wish to conquer the Morea at the time, merely to instill terror, and the Turks soon left the peninsula, devastated and depopulated. Constantine and Thomas were in no position to ask for a truce and were forced to accept Murad as their lord and pay him tribute, promising to never again restore the Hexamilion wall.
Their former co-despot Theodore died in June 1448, and on 31 October of the same year, Emperor John VIII died. The potential successors to the throne were Constantine, Demetrios and Thomas. John had not formally designated an heir, though everyone knew he favored Constantine and ultimately, the will of their mother, Helena Dragaš (who also preferred Constantine), prevailed. Both Thomas, who had no intention of claiming the throne, and Demetrios, who most certainly did, hurried to Constantinople and reached the capital before Constantine. Though Demetrios was favored by many due to his anti-unionist sentiment, Helena reserved her right to act as regent until her eldest son, Constantine arrived, stalling Demetrios's attempt at seizing the throne. Thomas accepted Constantine's appointment and Demetrios, who soon thereafter joined in proclaiming Constantine as his new emperor, was overruled. Byzantine historian and Palaiologos loyalist George Sphrantzes then informed Sultan Murad II, who also accepted the ascension of Constantine, now Emperor Constantine XI. In order to remove Demetrios from the capital and its vicinity, Constantine made Demetrios Despot of the Morea, to rule the despotate together with Thomas. Demetrios was granted Mystras and primarily ruled the southern and eastern parts of the despotate, with Thomas ruling Corinthia and the north-west, variously using Patras or Leontari as his capital.