When am I?

Halley's comet passed on by
so clearly visible to the eye
it was embroidered in a tapestry
so centuries later the world could see

Then in October at Hastings
old Harold got a right pasting
he had no idea he would die
from an arrow in the eye

Upon his death the Duke of Normandy
was crowned England's King on Christmas day
he reclaimed what he though was his
and so ended the dark ages

Can you guess what year this is
in my little history quiz?