Methodius I was a Patriarch of Constantinople. Before he became the patriarch, he spent years fighting the second outbreak of the iconoclast persecution in the Eastern Church. Niκephoros, the patriarch of Constantinople, was banished and replaced with an iconoclastic patriarch. Methodius, a monk, was sent by the deposed patriarch to Rome to report the matter. After several years in Rome, and a change in the eastern emperor (Leo V was murdered and replaced by Michael II), Methodius returned with a letter from the pope that attempted to persuade the eastern emperor to change his ways and restore Niκephoros. That didn’t work out so well. Methodius was scourged and imprisoned. After 7 years, Methodius was let out of prison, and he defended the icons even more strongly than before.
When the emperor Michael died, his son Theophilus re-invigorated the persecution. Methodius, after going toe-to-toe with the emperor was again scourged and imprisoned. He managed to escape after a day this time, and continued to work on the emperor.
After Theophilus, the Iconoclast persecution was brought to an end. Theodora, Theophilus’s wife and the regent for Michael III, restored images and freed the prisoners. The current patriarch of Constantinople was an unrepentant iconoclast setup by the government. He was deposed and Methodius was made patriarch. He restored the icons to the Hagia Sophia (yeah, that Hagia Sophia, the one that was a Catholic or Orthodox church from 562 to 1453) in a solemn procession and deposed many iconoclast bishops throughout his patriarchate. The restoration, or “Feast of Orthodoxy” is still celebrated in Byzantine Churches today.
Methodius is a Catholic and an Orthodox saint. He is named in the Roman Martyrology on June 14.