585 BC A solar eclipse occurred, as predicted by Greek philosopher and scientist Thales, while Alyattes was battling Cyaxares in the Battle of the Eclipse, leading to a truce. This was one of the cardinal dates from which other dates can be calculated.
1291 Acre, in the Kingdom of Jerusalem, fell to the Moslems, ending the Crusades.
1588 The Spanish Armada, with 130 ships and 30,000 men, set sail from Lisbon heading for the English Channel. (It would take until May 30 for all ships to leave port).