Story Behind Coventry Carol

The "Coventry Carol" is an English Christmas carol dating from the 16th century. The song originates from an English Christmas play about the Bible story of Jesus' birth. The carol was traditionally performed in Coventry in England as part of a mystery play called The Pageant of the Shearmen and Tailors. The play depicts the Christmas story from chapter two in the Gospel of Matthew: the carol itself refers to the Massacre of the Innocents, in which Herod ordered all male infants under the age of two in Bethlehem to be killed, and takes the form of a lullaby sung by mothers of the doomed children.
Within the pageant, the carol is sung by three women of Bethlehem, who enter on stage with their children immediately after Joseph is warned by an angel to take his family to Egypt 

Refrain:
Lully, lulla,
thou little tiny child,
by by, lully lullay.

1 O sisters too,
how may we do
for to preserve this day

this poor youngling,
for whom we do sing
by by, lully lullay?

2 Herod the king,
in his raging,
charged he hath this day

his men of might,
in his own sight,
all young children to slay.

3 That woe is me,
poor child for thee!
and ever morn and day,

for thy parting
neither say nor sing
by by, lully lullay! [Refrain]