 Complete the following phrase:  In 1820, he joined the British East India Companys army, transferring into the British Army in 1825. As aide-de-camp to the British envoy to Persia, he witnessed fighting during the war between Persia and Russia in 1826 and in 1829 was present in the Balkans during the Russo-Turkish War, 1828-1829. From 1832 to 1834, he witnessed the 