“O Joyful Light! Light and Holy Glory of the Father Immortal, the heavenly, holy, the Blessed One, O Jesus Christ! Now that we have reached the setting of the sun, and see the evening light, we sing to God, Father, Son, and Holy Spirit. It is fitting at all times to raise a song of praise in measured melody to you, O Son of God, the Giver of Life. Behold, the universe sings your glory.” 

– “O Joyful Light” – oldest known Christian Hymn sung at Vespers