- 1066 25 Sep Harold II of England defeats an invasion by Harald Hardrada of Norway, at Stamford Bridge near York.
- 1643 25 Sep The 'Solemn League and Covenant' between English and Scottish parliaments against Charles I is concluded.
- 1915 25 Sep The British Army first uses poison gas at Loos, France, but ends up gassing many of its own troops.

