As excerpted from the Antiochian Archdiocese website.

St. Thais of Egypt led a depraved and dissolute life during the 4th century. She was famed for her beauty, leading many on the path to perdition.

Stories about Thais spread throughout all Egypt, eventually reaching even St. Paphnutius, a strict ascetic who had converted many to salvation. Paphnutius dressed himself in worldly attire and went to Thais, giving her money as though he wished to pay for her favors. He pretended to be afraid that someone would see them, so he asked her if there was a place where they would not be discovered. Thais said that they could lock the door and enjoy complete privacy. “But if you fear God,” she said, “there is no place where you can hide from Him.” Seeing that she knew about God and the punishment of the wicked, the Elder asked why she led a sinful life and enticed others to ruin their souls. He told her about the eternal punishment she would have to face for her own sins, and for the people who had been corrupted and destroyed by her.

The words of St. Paphnutius so affected Thais that she gathered up all her riches acquired through her shameful life and set them on fire in the city square. St. Paphnutius shut her up in a small cell, where for three years she dwelt in seclusion. Turning toward the East, Thais constantly repeated the prayer, “My Creator, have mercy on me!”

“From the moment I entered into the cell,” said Thais to Paphnutius before her death, “all my sins constantly were before my eyes, and I wept when I remembered them.” St. Paphnutius replied, “It is for your tears, and not for the austerity of your seclusion, that the Lord has granted you mercy.”

St Thais was ill for three days, then fell asleep in the Lord. This woman, who had been a harlot and a sinner, entered the Kingdom of God. St. Paul the Simple saw in a vision the place prepared for St. Thais in Paradise.

Troparion (Tone 4) –

O God of our fathers, do not take your mercy from us, but ever act towards us according to your kindness and by the prayers of your Holy Thais, guide our lives in peace!

Kontakion (Tone 2) –

Let us praise the blessed Thais, the truly fruitful branch from a corrupt root, the sweet stream from a salty source, the image of repentance and rule of patience! Once a vessel of sin, she is now the chosen vessel of grace! Let us cry aloud to her: O Venerable Thais, entreat Christ God that our souls may be saved!