On the twenty-seventh of this month [February], we commemorate the Holy Martyr Gelasios who was formerly a mime, who was ordered to parody Holy Baptism, and was truly baptized and perfected by the sword.
Verses
Intending to incite laughter through Illumination you laughed at error,
Having been washed Gelasios is beheaded.
Gelasios, of the village Mariamne near Damascus, was an actor. In a performance at Heliopolis of Syria, he played the part of a catechumen in a dramatized parody of the Christian's Mystery of Holy Baptism. As he was immersed in the waters, the audience laughed. Divine Grace, however, wrought a miracle, and Gelasios emerged from those waters transformed. As the play continued and he was garbed in the white gown of the newly-illumined, he declared before the crowd, "I am a Christian. When I was under those waters, I was awestruck by the glory that I beheld. I am now ready to be slain on behalf of Christ!" The rest of the cast, knowing that these lines were not in the script, were aghast. The audience soon understood that Gelasios was not jesting but instead meant every word of his public confession. Roused to fury, the audience came down upon Gelasios, who was still clad in white, and dragged him out of the theatre and stoned him. Christians who witnessed the stoning, afterward took up his honorable relics and returned with them to their own country. A church was built over the martyrs tomb.
Mimes in Ancient Rome
The dominant genre in Roman theatre was the mime drama. This was made up of short, simple improvisatory scenes brilliantly portraying the daily round: satirizing people, manners and actions; demythologizing episodes from myth and debunking classical tragedy. Coarse witticisms and untrammelled grossness were the staple of these mimes, their immediate aim being to get a mimicus risus, a belly-laugh out of the audience.
The mime was both in prose (mimology) and in verse (mimody). The set was plain, and the mime could perform anywhere s/he pleased, from the Forum to the banqueting rooms of private houses. There were no chorus or characters, and the actors usually played barefoot. This was the one theatrical genre in antiquity where women appeared on stage.
The mime, which started to flourish in the Hellenistic and Roman periods, is thought to have originated in classical Sicily. It reached its peak with the works of the famous Augustan mime writer, Philistion of Asia Minor, of whom it was said that he quite literally laughed himself to death.
The pantomime developed from the mime. The whole play was performed by a single player - a "quick-change" mime dancer. This was a single 'mute' actor - the arch-mime - who, with rhythmic movements and gestures and the help of just one mask with three or five faces, presented every one of the characters and episodes in the play, down to animals, birds and the elements of Nature.
The Alexandrians Pylades and Bathyllus are thought to have introduced the danced mime to Rome, the city which embraced it more than any other. But the cultural trends of the Imperial Age favoured the ecumenical spread of the 'language of movement', making the mime outstandingly popular throughout the Empire, accessible as was it to the various peoples under Roman dominion, crossing barriers of language and culture.
Source
* Very similar accounts of the conversion of actors are found in the lives of Saints Porphyrios (Sep. 15, Nov. 4), Ardalion (Apr. 14), Glaukos (not commemorated) and Genesios of Rome (Aug. 25 in the Latin Church).