A lot of people realize that, in Harry Turtledove’s alternate Byzantium, the god “Phos” (Light) is both an alternate Ahura Mazda, as well as a way to comment on Byzantine Christianity without commenting. But he’s also referring to the famous Christian hymn “Phos Hilaron”. Like “Inventor Rutili”, it’s a lamplighting hymn. IIRC, Turtledove even quotes the thing in his trilogies, but I don’t know how many people catch it.
Here’s the hymn in Greek, sung to the “ancient” melody (“melos archaion”) by the late Fr. Dositheos, a blind monk from Mount Athos, with a drone backup (Kevin tells me below that the sound’s called an “ison”) from the monastery choir. From analogion.com’s very interesting Byzantine music resource pages.
For those of us who don’t read Greek letters, here’s the transliterated lyrics so you can sing along:
Phos hilaron aghias dóxis, athanátou Patrós, ouraníou aghiou mákaros, Iisoú Hristé, elthontes epí tin ilíou dysin, idóntes phos esperinón, hymnoumen Patéra, Yión, kai ághion Pnevma, Theón, Axion se en pási kairoís hymneisthai, phonés aisíais, Yié Theoú, zoín o didoús, dió o kósmos se doxázei.
The interesting bit is that, although you hear its great solemnity when sung here as a church hymn (and rightly so), after a while the underlying bounciness starts to come through.
Here’s three totally different settings (in English translation) dug up by Chantblog. I don’t know if any of the music is the same as the tune above. Oremus has “O gladsome light” TTTO “Le Cantique de Simeon” by Louis Bourgeois.