September 12 is the 255th day of the year (256th in leap years) in the Gregorian calendar. There are 110 days remaining until the end of the year.
Events:
490 BC – Battle of Marathon: The conventionally accepted date for the Battle of Marathon. The Athenians and their Plataean allies, defeat the first Persian invasion force of Greece.
372 – Sixteen Kingdoms: Jin Xiaowudi, age 10, succeeds his father Jin Jianwendi as Emperor of the Eastern Jin dynasty.
1185 – Emperor Andronikos I Komnenos brutally put to death in Constantinople.
1213 – Albigensian Crusade: Simon de Montfort, 5th Earl of Leicester, defeats Peter II of Aragon at the Battle of Muret.
1229 – Battle of Portopí: The Aragonese army under the command of James I of Aragon disembarks at Santa Ponça,Majorca, with the purpose of conquering the island.
1309 – The First Siege of Gibraltar takes place in the context of the Spanish Reconquista pitting the forces of the Kingdom of Castile against the Emirate of Granada resulting in a Castilian victory.
1609 – Henry Hudson begins his exploration of the Hudson River while aboard the Halve Maen.
1683 – Austro-Ottoman War: Battle of Vienna – several European armies join forces to defeat the Ottoman Empire.
1814 – Battle of North Point: an American detachment halts the British land advance to Baltimore in the War of 1812.
1846 – Elizabeth Barrett elopes with Robert Browning.