Nicholas Mysticus

Byzantine patriarch

Written by

The Information Architects of Encyclopaedia Britannica

Last updated

July 1, 2026

Quick Summary

Nicholas Mysticus was a Byzantine patriarch of Constantinople who served two terms: 901–907 and 912–925. He was a close associate of Patriarch Photius and began his career in the civil service before becoming a monk.1

Nicholas is known for his role in the attempted reunion of the Greek and Roman churches and for his involvement in the "tetragamy controversy," which concerned the legality of a fourth marriage in the Eastern Orthodox Church. He refused to grant Emperor Leo VI a dispensation for a fourth marriage, leading to his banishment. He was later recalled and played a role in settling disputes within the Eastern Orthodox Church and fostering harmony with the Western Church. Nicholas is revered as a saint in the Eastern Orthodox Church.1

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

2 Britannica Sources

Ask Britannica AI about this topic

Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.

Constantine VII Porphyrogenitus
…bitter opposition of the patriarch Nicholas Mysticus. It was Leo’s fourth marriage, and the Greek church normally forbade a widower to remarry more than once. As the infant was Leo’s only male offspring, he had to be accepted and, in 911, was proclaimed coemperor. But, on the death of his…
Read More
…bitter opposition of the patriarch Nicholas Mysticus. It was Leo’s fourth marriage, and the Greek church normally forbade a widower to remarry more than once. As the infant was Leo’s only male offspring, he had to be accepted and, in 911, was proclaimed coemperor. But, on the death of his…
Read More