Historians rank it among the major battles that changed the course of history.
Harold Godwin was chosen king of England in 1066, after Edward the Confessor died. But William of Normandy claimed that Edward, his cousin, had promised him the English throne. Harold prepared to defend the coast against an attack, as William enlisted knights from Normandy and northern France. But the king of Norway suddenly invaded northern England to claim the throne. Harold took his troops north on a forced march.