The Anglo-Persian War lasts between November 1, 1856 and April 4, 1857, and is fought between the United Kingdom and Persia (at this time ruled by the Qajar dynasty).
In the war, the British oppose an attempt by Persia to reacquire the city of Herat, which is nominally part of Afghanistan (at this time a very loose entity) but which had been part of Persia under the Safavid dynasty.
Persia ultimately agrees to surrender its claims to the city.