Basil the Great, writing in the fourth century CE, already refers to this hymn as of unknown but clearly ancient authorship, treating it as received tradition rather than as a recent composition even in his own time, which is part of why it is generally regarded as the oldest Christian hymn still in continuous liturgical use outside scripture itself, its actual date of composition receding earlier than any named author can be confidently attached to. Its place in the Byzantine liturgical day, sung specifically at the lighting of the evening lamps during Vespers, ties its text directly to that physical moment, addressing the light itself as the hymn is sung while the lamps are being lit, a coordination of text and physical ritual action distinctive among the hymns recorded in this atlas.
Its adoption into Western Christian practice happened considerably later and through translation: nineteenth century English hymn writers, including John Keble, whose 1834 rendering became known by its opening words, O Gladsome Light, brought the ancient Greek text into English verse for use in Anglican evening prayer, and versions descended from or inspired by that translation subsequently appeared in various Western liturgical books for evening worship, so a hymn composed in Greek in the earliest Christian centuries and preserved continuously in Eastern Orthodox Vespers only reached most Western worshippers, if at all, through nineteenth century English poetic translation rather than through any earlier direct liturgical borrowing between East and West.