A member of the first British military mission to Iran (1810), he was killed in action while serving on the Iranian side during the Russo-Persian War of 1804–1813.

[2] Christie and Pottinger disguised themselves as horse dealers, and travelled north from the Makran coast to Nushki, where the two separated in March of 1810.

A manuscript of Christie's travel journal is appended to Pottinger's account of his expedition which provided the first reliable information about these territories.

[2] At the request of Harford Jones (later named Harford Jones-Brydges), the British envoy to Iran, Christie and a number of other British officers entered into military service with Iran hence forming the core of the military mission provided for in accordance with the Preliminary Treaty of Friendship and Alliance that Jones had negotiated with Fath-Ali Shah Qajar (r. 1797–1834) on 17 June 1809.

[4] During the battle, Christie and Lindsay reportedly threw themselves into the thick of the fighting, thereby gaining the admiration of the Iranians and proving that they would not refrain from attacking fellow Christians.