The Battle of Stanford Bridge

In 1065, the leading aristocracy of Northumbria rebelled against Tostig. He was exiled and replaced by another English Earl Mocar. In September 1066, following an alliance with a man described as the last of the great Vikings, Harold Hardrada, King of Norway, Tostig invaded England. So did Harold have to leave a significant amount of his army in the north of England to face William in the south? Well, he had, he had marched north to defeat Tostig and Hardrada at a major battle at Stanford Bridge on the 25th of September. At that battle, the English forces decisively defeated the Norwegian invaders. So it was a