The Icon of the Lord Jesus Christ, "Not Made With Hands".
At the time when our Lord preached the Good News and healed every illness and infirmity of men, there lived in the city of Edessa on the shore of the Euphrates Prince Abgar who was completely infected with leprosy. He heard of Christ, the Healer of every pain and disease and sent an artist, Ananias, to Palestine with a letter to Christ in which he begged the Lord to come to Edessa and to cure him of leprosy. In the event that the Lord was unable to come, the prince ordered Ananias to portray His likeness and to bring it to him, believing that this likeness would be able to restore his health.
The Lord answered that He was unable to come, for the time of His passion was approaching took a towel, wiped His face and, on the towel, His All-pure face was perfectly pictured. The Lord gave this towel to Ananias with the message that the prince will be healed by it, but not entirely, and later on, He would send him a messenger who would erase the remainder of his disease.
Receiving the towel, Prince Abgar kissed it and the leprosy completely fell from his body but a little of it remained on his face. Later, the Apostle Thaddaeus, preaching the Gospel, came to Abgar and secretly healed and baptized him. The prince then destroyed the idols which stood before the gates of the city and above the gates he placed the towel with the likeness of Christ attached to wood, framed in a gold frame and adorned with pearls. Also, the prince wrote beneath the icon on the gates: "O Christ God, no one will be ashamed who hopes in You." Later, one of Abgar's great grandsons restored idolatry and the bishop of Edessa came by night and walled up that icon over the gates. Centuries have passed since then.
During the reign of Emperor Justinian, the Persian King Chozroes attacked Edessa and the city was in great hardship. It happened that Eulabius, the Bishop of Edessa, had a vision of the All-Holy Theotokos who revealed to him the mystery of the sealed wall and the forgotten icon. The icon was discovered and, by its power, the Persian army was defeated.
From the Prologue from Ochrid.