- 48 BC 9 Aug Julius Caesar defeats Pompey at the Battle of Pharsalus, giving Caesar absolute control of Rome.
- 378 9 Aug The Goths destroy the eastern Roman army and kill the emperor Valens at the Battle of Adrianople.
- 1945 9 Aug An atom bomb is dropped on the Japanese port of Nagasaki by the US bomber 'Bock's Car'.

