Britannica AI Icon
Adding us as a Preferred Source tells Google you trust our content, so our articles show up more often in your Google Search, Discover feed, and AI Overviews.
verifiedCite
While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions.
Select Citation Style
Feedback
Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login).
Thank you for your feedback

Our editors will review what you’ve submitted and determine whether to revise the article.

John IV Lascaris (born December 25, 1250—died c. 1305) was the emperor of Nicaea whose brief reign as a minor was filled with intrigue and conspiracies that culminated in the seizure of power by Michael Palaeologus, the future Byzantine emperor Michael VIII.

John IV’s parents were the Nicaean emperor Theodore II Lascaris (reigned 1254–58) and Helen, a daughter of the Bulgarian tsar John Asen II. Eight years old when his father died, John was advised by his regent George Muzalon, a trusted friend of the former emperor. But Muzalon was assassinated nine days after Theodore’s death by associates of Michael Palaeologus, who then became regent. Michael proclaimed himself emperor and was crowned coemperor with John in December 1258. He was crowned sole ruler in August 1261 in the church of Hagia Sophia in Constantinople, after his troops retook the city from its Latin rulers. Relegated to the background since 1258, John IV was then blinded and imprisoned in a fortress on the south shore of the Sea of Marmara.

This article was most recently revised and updated by Encyclopaedia Britannica.
Discover the fascinating events that shaped the world, straight from our editors.
By clicking “Sign Up”, you consent to the Britannica Privacy Policy and Terms of Use.