Name the song

Explanation

"This Endris Night" is a 15th-century English Christmas carol. It has also appeared under various other names and spellings. It has been praised for the unusual delicacy and lyrical flourish for a poem of the period, and it goes like this: Thys endris nygth. I saw a sygth, A stare as brygt as day. And ever among. A mayden song. Lullay, by by, lullay.