When Edward the Confessor died he left no direct heir, and the throne of England passed to Harold.
However, William of Normandy claimed that Edward had promised the crown to him, and indeed that Harold himself had sworn a sacred oath to relinquish his claim in William's favour.
William prepared an invasion fleet and, armed with a papal bull declaring his right to the throne, he crossed the English Channel to land near Pevensey. Harold, in the meantime, had another threat to concern him; his brother Tostig allied with Harald Hardrada of Norway and landed in the north of England. They took York, but Harold defeated them soundly at the Battle of Stamford Bridge. No sooner had the battle dust settled than Harold received news of William's invasion in the south. He marched his tired men from York to Sussex, arriving there on October 13 to face the Normans. Harold took up a defensive position on a high ridge known as Senlac. The battle began with devastating volleys of stone missiles hurled into the Norman infantry by the Saxon "fyrd", or irregular troops levied from the shires.
William himself led the centre of the Norman army, and it is said that he carried into battle some of the holy relics upon which Harold had sworn to cede the crown to him.
The Norman infantry made no dent in the Saxon lines, and the cavalry fared no better. But when some of the Norman horsemen turned and fled, a large group of Saxons left their position to chase them.