The regiments first action was during the Anglo-Persian War in 1856, for which they were awarded the battle honours of "Persia", "Reshire", "Bushire" and "Koosh-ah". During World War I they were attached to the 6th (Poona) Division and served in the Mesopotamian campaign. They fought in the Battle of Basra, the Battle of Qurna, the Battle of Es Sinn before being delivered a setback at the Battle of Ctesiphon. Following this engagement, they withdrew to Kut. Trapped in the city during the Siege of Kut they were forced to surrender after 147 days. A second battalion was raised from men on leave and reinforcements and sent to Mesopotamia.