16th century English Christmas carol, also known as "Lully, Lullay" (which one web page at http://www.cvc.org/christmas/coventry.htm says is old slang for "I saw! I saw!")
Lullay, Thou little tiny Child,
By, by, lully, lullay.
Lullay, Thou little tiny Child,
By, by, lully, lullay.
O sisters too, how may we do,
For to preserve this day.
This poor youngling for whom we sing
By, by, lully, lullay.
Herod the king, in his raging,
Charged he hath this day.
His men of might, in his own sight,
All young children to slay.
That woe is me, poor Child for Thee!
And ever morn and day,
For thy parting neither say nor sing,
By, by, lully, lullay.