Φῶς ἱλαρὸν/Phōs Hilaron (O Cheerful Light) is a brief, ancient hymn that has formed part of vespers in churches of the eastern tradition from early times to the present day, and has more recently been adopted by many western churches. Although traditionally associated with a lamp-lighting ceremony, the light addressed is not that of a lamp but Jesus Christ, identified with the glory of the Father. After a central Trinitarian doxology, the …