Why did king harold II lose against william, duke of normandy at the battle of hastings in 1066?
Psycholgical warfare. William thought to get a papal banner before he started which he unfurled at Pevensey. This caused Harold who up until that point had been resolute to hestitate. And as they say “he who hesitates, is lost.” He was killed by a Norman and that broke the resolve of his men. William of Normandy (aka Duke William, William the Bastard, William the Conqueror) had meet with the previous king of England, Edward the Confessor several years earlier and Edward (who had no children) agreed to name him as his choice of sucessor. However, there was a fundamental misunderstanding. William thought that this meant, as per Norman custom, that he was de facto the next king of England. However at the time in England, the Saxons chose their kings by council. A king could indicate his choice of sucessor, but that did not mean that the Council (called the Witan) would actually go with that choice. And in this case, they chose Harold Godwinson instead. At least three men disagreed: Harold
