"In the time of Diocletian, a fierce persecutor of Christians called Philomarchus came to Sebaste. He arrested and killed many Christians in the town. When he saw Athenogenes and his disciples, he told the elder to sacrifice to the idols, that they should not perish as had the other Christians. Athenogenes replied: 'O Torturer, those whom you describe as having perished have not perished, but are in heaven and make merry with the angels!' There was a touching moment when a deer, which had been hand-fed by the compassionate Athenogenes, ran up to him and, seeing him in such straits, shed tears. Wild animals of the hills had more pity on the martyrs than did the pagans! After harsh torture, during which an angel of God comforted them, they were all beheaded, first the priests and fellow workers of Athenogenes and then Athenogenes himself, and went to their heavenly home in the year 311." (Prologue)
  The Great Horologion adds "There is a second Martyr Athenogenes commemorated today, mentioned by St Basil... it is said that as this Athenogenes approached the fire, wherein he was to die a martyric death, he chanted the hymn O Joyous Light in praise of the Holy Trinity." This is one way that we know that the vesperal hymn Gladsome Light was in use before the time of St Basil the Great.