As Slaughter Crept unto the Sheep

Turn in my lord! Turn in my lord!
But water I cannot afford.
Some milk is best at your request.
Now hide you and get you some rest.
But as he sleep, to him she creep,
As slaughter crept unto the sheep.
Then with a nail, his head impale,
So saved the day lady __________.

What is the lady’s name?

HINT 1: