Genesius was an actor in the third century and his story is one that is an ancient one, though nonetheless impressive in terms of his faith. He was performing on the stage in front of Diocletian (an emperor known for hating Christians) in Rome. He was portraying a catechumen that was about to be baptized in the play, which was satirizing the sacrament. During the ceremony, it was said that he suddenly converted to Christianity.

He declared this to the Emperor and with rage, Diocletian turned him over to the Plautian and they tortured him, trying to force his sacrifice to the pagan Gods. Genesius clung to his Christian faith and when they realized they would not be able to change his mind, he was beheaded.

St. Genesius is the patron saint of actors. His day of feast is the 25th of August. He is commonly portrayed with a string instrument in his hand.