Here is a Russian icon from the Annunciation Cathedral in Solvuichegodsk/Solvychegodsk:
It depicts the “Fool for Christ’s Sake” Isidor/Isidore of Rostov.
Isidore is said to have been of Slavic stock and a wealthy family, and to have lived first in Brandenburg, in the eastern part of Germany once known as Prussia. He at some time converted to Russian Orthodoxy, and left Prussia for Russia. There he wandered about a bit, then decided on the city of Rostov, where he set himself up as a “Holy Fool” — that peculiar category of Eastern Orthodox piety. Holy fools live in extreme poverty, and above all pretend to be crazy, supposedly to avoid the sin of pride and to live lives of humility while they are ridiculed and scorned by the public. Oddly enough, it never seems to have occurred to them that behaving like a lunatic is much more likely to draw ongoing public attention than just living a quiet and pious life. And of course it was never quite certain where the line between pretending to be crazy and actually being crazy was to be drawn.
In any case, Isidore built himself a crude hut in the middle of a swampy pool, and there he took took up residence.
Of course the usual miracle stories accompany him. The most prominent of them relates that a Rostov merchant was at sea in a terrible storm, and the ship was in danger of breaking apart. The sailors, in imitation of the story of Jonah in the Old Testament, decided that this misfortune must be the result of having a person very displeasing to God on board, and as in the tale of Jonah, they “cast lots” to decide who it was.
The man found responsible was the Rostov merchant. They tossed him into the sea, along with a wooden plank. The merchant was in great distress. Just then the Holy Fool Isidore came walking across the water to the merchant, who recognized him and began to plead for his help. Isidore put the merchant on the wooden plank, and it floated after the ship (which obviously was saved), catching up with it. Soon the merchant found himself back on board. The sailors who had thrown him into the sea saw this as a miracle, but the merchant, following the command of Isidore, would not reveal that the Holy Fool had appeared and saved him.
There are of course more miracle stories associated with Isidor, who died on May 14, 1474.
If we look at the title inscription, we can see that it identifies him as:
АГИОС ПРАВЕДНЫЙ ИСИДОР РОСТОВСКИЙ
AGIOS PRAVEDNUIY ISIDOR ROSTOVSKIY
“Holy Righteous Isidore of Rostov”
The Agios at the beginning is just the borrowed Greek word Hagios, meaning “holy/saint.”
If you look at the right hand of Isidore as he looks up toward Mary and Jesus in heaven, you can see that the fingers very obviously form the blessing sign characteristic of the Old Believers. That is not surprising, given that the icon shown dates to the first half of the 17th century.