"Theodore I Laskaris or Lascaris (Greek: Θεόδωρος Κομνηνὸς Λάσκαρις, romanized: Theodōros Komnēnos Laskaris; c. 1175 – November 1221) was the first Emperor of Nicaea—a successor state of the Byzantine ...
Empire—from 1205 to his death. Although he was born to an obscure Byzantine aristocratic family, his mother was related to the imperial Komnenos clan. He married a younger daughter of the Byzantine Emperor Alexios III Angelos in 1200. He received the title of despot before 1203, demonstrating his right to succeed his father-in-law on the throne.
The Fourth Crusade forced Alexios III to flee from Constantinople in 1203. Theodore was imprisoned by the crusaders (commonly referred to as "Latins" by the Byzantines), but he escaped. After crossing the Bosporus into Asia Minor (in present-day Turkey), he started to organise the local Greeks' resistance against the Latins in Bithynia in his father-in-law's name. He concluded an alliance with the Seljuq Sultan of Rum, but he could not stop the Latins' expansion. Neither could he prevent a claimant to the imperial throne, Alexios Komnenos, from establishing a Byzantine successor state, the Empire of Trebizond, in northern Asia Minor. Theodore's position consolidated only after Tzar Kaloyan of Bulgaria inflicted a crushing defeat on the Latins in the Battle of Adrianople (in Thrace) in 1205." - (en.wikipedia.org 11.08.2021)
