The Anglo-Persian War or the Anglo-Iranian War lasted between 1 November 1856 and 4 April 1857, and was fought between the United Kingdom and Iran, which was ruled by the Qajar dynasty. The war had the British oppose an attempt by Iran to press its claim on the city of Herat. Though Herat had been part of Iran under the Qajar dynasty when the war broke out, it had declared itself independent under its own rebellious emir and placed itself under the protection of the British in India and in alliance with the Emirate of Kabul, the predecessor of the modern state of Afghanistan. The British campaign was successfully conducted under the leadership of Major General Sir James Outram in two theatres: on the southern coast of Persia near Bushehr and in southern Mesopotamia.

Qajar Iran, also referred to as Qajar Persia, the Qajar Empire, Sublime State of Persia, officially the Sublime State of Iran and also known as the Guarded Domains of Iran, was an Iranian state ruled by the Qajar dynasty, which was of Turkic origin, specifically from the Qajar tribe, from 1789 to 1925. The Qajar family took full control of Iran in 1794, deposing Lotf 'Ali Khan, the last Shah of the Zand dynasty, and re-asserted Iranian sovereignty over large parts of the Caucasus. In 1796, Agha Mohammad Khan Qajar seized Mashhad with ease, putting an end to the Afsharid dynasty. He was formally crowned as Shah after his punitive campaign against Iran's Georgian subjects.