On 6th January 1066, the Witan decided that Harold Godwinson was to be the next king of England. Harold was fully aware that Harald Hardrada of Norway and William of Normandy would probably try to take the throne from him. He believed that the Normans posed the main danger and he positioned his troops on the south coast of England.
Harold's soldiers were made up of housecarls and the fyrd. Housecarls were well-trained, full-time soldiers who were paid for their services but the fyrd were working men who were called up to fight for the king in times of danger.
King Harold waited all summer but the Normans did not arrive. By September Harold's army was running out of food. Members of the fyrd were also keen to harvest their own fields so Harold sent them home. Harold also sent his navy back to London.
In early September King Harold heard that Harald Hardrada of Norway had invaded northern England. The messenger told Harold that Hardrada had come to conquer all of England. It is said that Harold replied: "I will give him just six feet of English soil; or, since they say he is a tall man, I will give him seven feet!"
With Harald Hardrada was Harold's brother Earl Tostig and 300 ships. Harold and what was left of his army headed north. On the way Harold heard that the Edwin, Earl of Mercia and the Morcar, Earl of Northumbria had been defeated by Hardrada and were considering changing sides.
Harold's arrival took Hardrada's troops, who were positioned at a place called Stamford Bridge, by surprise. It was a hot day and the Norwegians had taken off their byrnies (leather jerkins with sewn-on metal rings). Harold and his English troops devastated the Norwegians. Both Harald Hardrada and Earl Tostig were killed. The Norwegian losses were considerable. Of the 300 ships that arrived, less than 25 returned to Norway.
While celebrating his victory at a Banquet in York, Harold heard that William of Normandy had landed at Pevensey Bay. King Harold immediately assembled the housecarls who had survived the battle and marched south. He travelled at such a pace that many of his troops failed to keep up with him. When Harold arrived in London he waited for the local fyrd to assemble and for the troops of the Edwin, Earl of Mercia and the Morcar, Earl of Northumbria to arrive from the north. After five days Harold decided to head for the south coast without his northern troops.
There was one of the Norwegians there who withstood the English host so they could not cross the bridge nor win victory. Then an Englishman shot an arrow, but it was no use, and then another came under the bridge and stabbed him under the corselet. Then Harold, king of the English, came over the bridge and his host with him, and there killed large numbers of both Norwegians and Flemings, and Harold let the king's son Hetmundus go home to Noway with all ships.
(SB2) Anglo-Saxon Chronicle, D Version, entry for 1066.
The Norwegians who survived took flight; and the English attacked them fiercely as they pursued them until some got to the ships. Some were drowned, and some burned, and some destroyed in various ways so that few survived and the English remained in command of the field. The king gave quarter to Olaf, son of the Norse king and all those who survived on the ships, and they went up to our king and swore oaths that they would always keep peace and friendship with this country; and the king let them go home with twenty-four ships.
(SB3) Florence of Worcester was a monk who wrote an account of the Battle of Stamford Bridge in about 1125.
Harold, king of the English, permitted Olaf, the son of the Norwegian king, to return home unmolested with twenty ships and the survivors, but only after they had sworn oaths of submission and had given hostages.