One army's forced march across England decided who'd be king in a single afternoon

On 14 October 1066, William, Duke of Normandy, defeated King Harold II near Hastings — days after Harold had force-marched his exhausted troops the length of England to fight off a separate Norwegian invasion. Harold was killed, traditionally said to have been struck in the eye by an arrow, though the sources conflict. William was crowned king by Christmas, and the Norman Conquest reshaped English language, law and land ownership for centuries.

— Wikipedia contributors, Battle of Hastings — 14 October 1066