Yusuf Çelebi (; 1392 – 1429)Alderson, A.D., The Structure of the Ottoman Dynasty, Clarendon Press, Oxford, 1955, table XXV. was an Ottoman prince and the son of Sultan Bayezid I who did not play an active role in the Ottoman Interregnum.Kastritsis, Dimitris J., The Sons of Bayezid: Empire Building and Representation in the Ottoman Civil War of 1402–1413, Brill, Leiden, 2007, p. 41. In Byzantine sources and prosopographical records, his name and title are preserved as Tzalapès kyr Dēmētrios ().Trapp, Erich et al., Prosopographisches Lexikon der Palaiologenzeit, Verlag der Österreichischen Akademie der Wissenschaften, Vienna, 1976–1996, entry n° 9082.Shukurov, Rustam, The Byzantine Turks 1204–1453, Brill, Leiden, 2016, p. 370.
He arrived in Constantinople after 1402. According to Laonikos Chalkokondyles, he came of his own accord, independently of the princely hostages handed over to Emperor Manuel II Palaiologos by Süleyman Çelebi,Chalkokondyles, Laonikos, Laonici Chalcocondylae Historiarum demonstrationes, ed. E. Darkó, 2 vols, Budapest, 1922–27, 1:167.15–17. probably to escape from the political crisis taking place during the civil war. Nevertheless, the Byzantine historian DoukasDucas, Istoria turco-bizantină (1341–1462), ed. Vasile Grecu, Bucharest, 1958, 21.4, p. 143. refers to his status as a hostage at the Byzantine court, where he was educated in a Byzantine school.Shukurov, Rustam, The Byzantine Turks 1204–1453, Brill, Leiden, 2016, p. 273. During this period, he befriended the future emperor John VIII Palaiologos, with whom he became very close friends.Shukurov, Rustam, The Byzantine Turks 1204–1453, Brill, Leiden, 2016, p. 274. He later converted to Christianity, taking the name "Dēmētrios".Kastritsis, Dimitris J., The Sons of Bayezid, Brill, 2007, p. 41. He died of natural causes in 1429.Alderson, A.D., The Structure of the Ottoman Dynasty, Oxford, 1955, table XXV.Shukurov, Rustam, The Byzantine Turks 1204–1453, Brill, Leiden, 2016, p. 372.
Yusuf was betrothed to Theodora, daughter of Despot Theodore I Palaiologos of the Despotate of the Morea, marking the only recorded occurrence of a male Ottoman dynast being integrated into the Byzantine imperial family through marriage.Sakaoğlu, Necdet, Bu mülkün kadın sultanları, 2008, p. 74. His upbringing in Constantinople is also cited as a prominent example of an Ottoman prince receiving a Byzantine education while retaining his native Turkish language.Shukurov, Rustam, The Byzantine Turks 1204–1453, Brill, Leiden, 2016, pp. 274–275.
References
Further reading Kastritsis, Dimitris J., The Sons of Bayezid: Empire Building and Representation in the Ottoman Civil War of 1402–1413, Brill, Leiden, 2007. Sakaoğlu, Necdet, Bu mülkün kadın sultanları, Oğlak Yayıncılık, 2008. Shukurov, Rustam, The Byzantine Turks 1204–1453, Brill, Leiden, 2016. Trapp, Erich et al., Prosopographisches Lexikon der Palaiologenzeit, Verlag der Österreichischen Akademie der Wissenschaften, Vienna, 1976–1996, entry n° 9082.