Reza Shah was brought to power by a British-engineered coup in 1925. Coup of 1921 was partially assisted by the British in order to prevent Russia making inroads into Iran. Reza Shah became the Minister of War, as well as the head of the Cossack Bridgade, and other the next few years it became evident that he, and not the Prime Minister, was the one who yielded power.In 1923 he was appointed PM. He became Shah in 1925.He aimed to modernise Iran, bringing it in-line with the West, undermining the institutions of Islam and the Ulama.