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Thomas I Komnenos Doukas
Lead seal of Thomas
Despot of Epirus
Reign	1297–1318
Predecessor	Nikephoros I Komnenos Doukas
Successor	Nicholas Orsini
Died	1318
Dynasty	Komnenos Doukas
Father	Nikephoros I
Mother	Anna Palaiologina Kantakouzene

Thomas I Komnenos Doukas (Latinized asComnenus Ducas) (Greek:Θωμάς Α΄ Κομνηνός Δούκας,romanized: Thōmas I Komnēnos Doukas) (c. 1285–1318) ruler ofEpirus from c. 1297 until his death in 1318.

Thomas was the son ofNikephoros I Komnenos Doukas andAnna Palaiologina Kantakouzene, a niece of EmperorMichael VIII Palaiologos. In 1290 he was conferred the court dignity ofdespotes by his mother's cousin, EmperorAndronikos II Palaiologos. Thomas' succession to his father's principality was endangered by the marriage of his sisterThamar Angelina Komnene toPhilip I of Taranto, a son of KingCharles II of Naples andMaria of Hungary in 1294. Although Philip had been promised to inherit Epirus in his wife's right, when Nikephoros died between September 1296 and July 1298, Anna secured the succession of her son Thomas and assumed the regency.

This isolated Epirus from its strongest ally and left it practically without outside support. Charles II of Naples demanded that Epirus be turned over to Philip and Thamar, but Anna refused, claiming that the arrangement had been broken when Thamar had been forced to abandon her Orthodox faith. To remedy this, Anna arranged for an alliance with theByzantine Empire and the marriage of young Thomas toAnna Palaiologina, the daughter of the co-EmperorMichael IX Palaiologos. The actual marriage took place in 1307 or 1313. In the meantime Charles II sent troops into Epirus, but they were repulsed and the Epirotes advanced into the Angevin lands in the westernBalkans, recoveringButrinto andNaupaktos in 1304–1305. A new Angevin invasion in 1307 ended with a compromise by which Philip of Taranto was ceded many of the fortresses that had been retaken by the Epirotes in the previous war.

Epirus gravitated increasingly into the Byzantine orbit until a private dispute between Epirote and Byzantine commanders sparked off a new conflict in 1315. The Byzantines raided as far asArta, and Thomas imprisoned his wife and entered into negotiations with Philip of Taranto. But before Epirus could enter into a new alliance with the Angevins he was murdered by his nephew, CountNicholas Orsini,Count of Cephalonia.

• Fine, John V. A. Jr. (1994) [1987].The Late Medieval Balkans: A Critical Survey from the Late Twelfth Century to the Ottoman Conquest. Ann Arbor, Michigan: University of Michigan Press.ISBN 0-472-08260-4.
• Kazhdan, Alexander, ed. (1991).The Oxford Dictionary of Byzantium. Oxford and New York: Oxford University Press.ISBN 0-19-504652-8.
• Nicol, Donald M. (1984).The Despotate of Epiros, 1267–1479: A Contribution to the History of Greece in the Middle Ages. Cambridge: Cambridge University Press.ISBN 978-0-521-13089-9.

• 1280s births
• 1318 deaths
• 13th-century despots of Epirus
• 14th-century despots of Epirus
• Byzantine people of the Crusades
• Medieval child monarchs
• Komnenodoukas dynasty
• Assassinated Byzantine people
• 14th-century murdered monarchs

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