John VIII Palaiologos in the context of "Demetrios Palaiologos"

Constantine XI Dragases Palaiologos or Dragaš Palaeologus (Greek: Κωνσταντῖνος Δραγάσης Παλαιολόγος, romanized: Kōnstantīnos Dragásēs Palaiológos; 8 February 1404 – 29 May 1453) was the last reigning Byzantine emperor from 23 January 1449 until his death in battle at the fall of Constantinople on 29 May 1453. Constantine's death marked the definitive end of the Eastern Roman Empire, which traced its origin to Constantine the Great's foundation of Constantinople as the Roman Empire's new capital in 330.

Constantine was the fourth son of Emperor Manuel II Palaiologos and Serbian noblewoman Helena Dragaš. Little is known of his early life, but from the 1420s onward, he repeatedly demonstrated great skill as a military general. Based on his career and surviving contemporary sources, Constantine appears to have been primarily a soldier. This does not mean that Constantine was not also a skilled administrator: he was trusted and favored to such an extent by his older brother, Emperor John VIII Palaiologos, that he was designated as regent twice during John VIII's journeys away from Constantinople in 1423–1424 and 1437–1440. In 1427–1428, Constantine and John fended off an attack on the Morea (the Peloponnese) by Carlo I Tocco, ruler of Epirus, and in 1428 Constantine was proclaimed Despot of the Morea and ruled the province together with his older brother Theodore and his younger brother Thomas. Together, they extended Roman rule to cover almost the entire Peloponnese for the first time since the Fourth Crusade more than two hundred years before and rebuilt the ancient Hexamilion wall, which defended the peninsula from outside attacks. Although ultimately unsuccessful, Constantine personally led a campaign into Central Greece and Thessaly in 1444–1446, attempting to extend Byzantine rule into Greece once more.

The term Roman empress usually refers to the consorts of the Roman emperors, the rulers of the Roman Empire. The duties, power and influence of empresses varied depending on the time period, contemporary politics and the personalities of their husband and themselves. Empresses were typically highly regarded and respected, and many wielded great influence over imperial affairs. Several empresses served as regents on behalf of their husbands or sons and a handful ruled as empresses regnant, governing in their own right without a husband.

Given that there were sometimes more than one concurrent Roman emperor, there were also sometimes two or more concurrent Roman empresses. For most of the period from 286 to 480, the Roman Empire, though remaining a single polity, was administratively divided into the Western Roman Empire and the Eastern Roman Empire. Through most of this period, the separated imperial courts had their own lines of succession, and as a result their own sequences of concurrent Roman empresses. The western empire fell in the late 5th century, its final empress being the wife of Emperor Julius Nepos. The eastern empire, often referred to as the 'Byzantine Empire' by modern historians, endured for almost another millennium until its fall through the fall of Constantinople in 1453. The final empress of the east, and final Roman empress overall, was Maria of Trebizond, wife of Emperor John VIII Palaiologos.

Đurađ Vuković Branković (Serbian Cyrillic: Ђурађ Вуковић Бранковић, Hungarian: Brankovics György; (22 February 1377 – 24 December 1456) served as the Serbian Despot from 1427 to 1456, making him one of the final rulers of medieval Serbia.

In 1429, Branković was formally granted the Byzantine title of Despot by Emperor John VIII Palaiologos. Like many Christian rulers in Eastern Europe at the time, his rule was marked by Ottoman vassalage. Despite this, he often sought to strengthen Christian alliances while maintaining the appearance of loyalty to the Ottoman Empire. Branković is also remembered for constructing the Smederevo Fortress in the city of Smederevo, which became the last capital of medieval Christian Serbia. He risked his life defending Belgrade with 3,000 knights against an Ottoman army of 60,000 under the command of Mehmed II the Conqueror.

Manuel II Palaiologos or Palaeologus (Greek: Μανουὴλ Παλαιολόγος, romanized: Manouḗl Palaiológos, pronounced [ma.nuˈil pa.le.oˈlo.ɣos]; 27 June 1350 – 21 July 1425) was Byzantine emperor from 1391 to 1425. Shortly before his death he was tonsured a monk and received the name Matthaios (Ματθαίος). Manuel was a vassal of the Ottoman Empire, which sometimes threatened to capture his territory outright. Accordingly he continued his father's practice of soliciting Western European aid against the Ottomans, and personally visited several foreign courts to plead his cause. These efforts failed, although an Ottoman civil war and Byzantine victories against Latin neighbors helped Manuel's government survive and slightly expand its influence. His wife Helena Dragaš saw to it that their sons, John VIII and Constantine XI, became emperors. He is commemorated by the Greek Orthodox Church on 21 July.

Helena Dragaš (Serbian: Јелена Драгаш, romanized: Jelena Dragaš; Greek: Ἑλένη Δραγάση, romanized: Helénē Dragásē; c. 1372 – 23 March 1450) was the Empress consort of the Byzantine Emperor Manuel II Palaiologos and the mother of the last two emperors, John VIII Palaiologos and Constantine XI Palaiologos. She served as the regent of the Byzantine Empire after the death of her son John VIII in 1448 until the enthronement of her son Constantine XI in 1449.

Born into Serbian nobility, she later became a nun and is venerated as a saint by the Eastern Orthodox Church under her monastic name, Saint Hypomone (Ὑπομονὴ), which is translated into English as Saint Patience.

Thomas Palaiologos (Greek: Θωμᾶς Παλαιολόγος; 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.