Simon the Tanner lived toward the end of the tenth century and many Coptic Christians in Egypt were engaged in handicrafts. Saint Simon worked in tanning, a craft known there till this day. This profession involved other crafts that depend on the process, from whence Simon carried several titles related to skins: Tanner, Cobbler, Shoemaker.
Caliph al-Muizz, who reigned during 972-975 AD,used to invite religious leaders to debate in his presence. In one of those meetings in which the patriarch Abraham, also known as Pope Abraam, and a Jew named Yaqub ibn Killis (and in another account of this story was known as Moses) were present, Abraham got the upper hand in the debate. Plotting to take revenge, Ibn Killis quoted the verse where Jesus Christ said in Gospel of Matthew: "He replied, “Truly I tell you, if you have faith as small as a mustard seed, you can say to this mountain, ‘Move from here to there,’ and it will move. Nothing will be impossible for you." (Matthew 17:20), and demanded that the Pope prove that his religion is right by means of this. After hearing ibn Killis say this, the caliph asked Abraham "What sayest thou concerning this word? Is it your gospel or not?" The patriarch answered "Yes, it is in it." After hearing Abraham answer, the caliph demanded that this very miracle be performed by Abraham’s hand or else he and all the Copts would be killed by the hand of the sword. It was then after hearing this that the patriarch asked for three days to complete the miracle.
Abraham compiled a group of monks, priests and elders. He told them to all stay in the church for three days for a penance. On the morning of the third day, Abraham was praying in the Hanging Church, when he saw Mary, mother of Jesus. The Holy Virgin told him to go to the great market. She said to him, "There thou wilt find a one-eyed man carrying on his shoulder a jar full of water; seize him, for he it is at whose hands this miracle shall be manifested. Abraham listened to Mary and went to the market where he met the man the Holy Virgin spoke of. The man was Simon the tanner, who had plucked out his eye because of a passage from the Bible: "If your right eye causes you to stumble, gouge it out and throw it away. It is better for you to lose one part of your body than for your whole body to be thrown into hell. 30 And if your right hand causes you to stumble, cut it off and throw it away. It is better for you to lose one part of your body than for your whole body to go into hell." (Matthew 5:29-30)
Simon told Abraham to go out with his priests and all his people to the mountain with the Caliph and all his soldiers. Simon then told Abraham to cry out "O Lord, have mercy" three times and each time to make the sign of the cross over the mountain. The patriarch followed the words of Simon and the mountain was lifted. After the miracle was performed in the presence of the Caliph, the Pope turned left and right looking for Simon, but he had disappeared and no one could find him. The Caliph turned to Abraham and said "O Patriarch, I have recognized the correctness of your faith."
In commemoration of this miracle, the Coptic Orthodox Church observes three extra days of fasting before the beginning of the Nativity Fast.