While nearly every educated person has heard of the Battle of Hastings, not as many know that it was the third of three decisive battles fought in a period of four weeks:; the others were Gate Fulford and Stamford Bridge. Had things gone differently, Hastings could have been fought between Harald of Norway and William the Conqueror. At any rate, this page has some good background and campaign notes for this critical period.
The Bayeux Tapestry is one of the more famous works of art in all of history. This site breaks the tapestry down into slices and describes the historical background behind each segment.