John IV Doukas Laskaris Ἰωάννης Δ΄ Δούκας Λάσκαρις Emperor and Autocrat of the Romans (Claimant) Portrait of John IV from a 15th-century manuscript Emperor of Nicaea Claimant Byzantine Emperor Reign 18 August 1258 – 25 December 1261 Predecessor Theodore II Laskaris Successor Michael VIII Palaiologos (Byzantine Empire) Born 25 December 1250 Constantinople Died c. 1305 Dynasty Laskarid dynasty Father Theodore II Laskaris Mother Elena of Bulgaria Religion Eastern Orthodoxy