She gave birth to her firstborn, a son.@Luke 2:7

15th Century ( pdf nwc).

This endris night1 I saw a sight
A star as bright as day;
And ever among a maiden sung,
Lullay, by by, lullay.

This lovely lady sat and sung,
And to her Child did say:
My Son, my Brother, Father, dear,
Why liest Thou thus in hay?

My sweetest bird, thus ’tis required,
Though Thou be King veray2;
But nevertheless I will not cease
To sing, By by, lullay.

The Child then spake in His talking,
And to his mother said:
“Yea, I am known as Heaven-King,
In crib though I be laid.

For angels bright down to Me light3:
Thou knowest ’tis no nay4:
And for that sight thou may’st delight
To sing, By by, lullay.

“Now, sweet Son, since Thou art a king,
Why art Thou laid in stall?
Why dost not order thy bedding
In some great kingès hall?

Methinks5 ’tis right that king or knight
Should lie in good array:
And then among, it were no wrong
To sing, By by, lullay.

“Mary mother, I am thy Child,
Though I be laid in stall;
For lords and dukes shall worship Me,
And so shall kingès all.

Ye shall well see that kingès three
Shall come on this twelfth day.
For this behest give Me thy breast
And sing, By by, lullay.

“Now tell, sweet Son, I Thee do pray,
Thou art my Love and Dear—
How should I keep Thee to Thy pay6,
And make Thee glad of cheer?

For all Thy will I would fulfill—
Thou knowest well, in fay7;
And for all this I will Thee kiss,
And sing, By by, lullay.

“My dear mother, when time it be,
Take thou Me up on loft,
And set Me then upon thy knee,
And handle me full soft.

And in thy arm thou hold Me warm,
And keep Me night and day,
And if I weep, and may not sleep,
Thou sing, By by, lullay.

“Now sweet Son, since it is come so,
That all is at Thy will,
I pray Thee grant to me a boon8,
If it be right and skill9,—

That child or man, who will or can
Be merry on my day,
To bliss Thou bring—and I shall sing,
Lullay, by by, lullay.

Some of the archaic terms require explanation:

1This endris night: The other night, a few nights ago
2Veray: True
3Light: Alight
4No nay: Undeniable
5Methinks: I think
6Pay: Satisfaction
7Fay: Faith
8Boon: Favor
9Skill: Reasonable