Saint Jonah was born in the city of Galich into a pious Christian family. The date of his birth is not known. His father was named Theodore. He was [[tonsure]]d as a [[monastic]] in one of the Galich monasteries when he was only twelve years old.
In the late 1420s, Jonah transferred to the [[Simonov Monastery]], where he again fulfilled various obediences for many years. He was close to Metropolitan [[Photius of Kiev|Photius]], who consecrated him [[Bishop]] of Ryazan and Murom. After Photius died in 1431, Grand Prince Vasili II (the Sightless) nominated Jonah for the position of [[metropolitan]] of Moscow, a position that required confirmation by the Patriarch of Constantinople, [[Joseph II of Constantinople|Patriarch Joseph II]]. Jonas was delayed in his journey to Constantinople until the end of 1435 by Vasili's war with the appanage princes
In the meantime, Isidore of Kiev had already been established as Metropolitan of Moscow by the Ecumenical Patriarch. After initially being accepted in Moscow and promising Vasili to be true to Orthodoxy, Isidore traveled, in 1438, to Florence, Italy to attend the [[Council of Florence]]. During the council, Isidore supported [[Catholicism]] and the re-unification of the Eastern and Western Churches. After returning to Moscow, as a papal legate, he substituted in the liturgy the name of the Pope in place of the name of the Patriarch. He was arrested immediately, but escaped and fled to Rome, where he died in 1462.