In addition to battling the armies of other European empires (and its former colonies, the United States, in the War of 1812), the British Army fought the Chinese in the First and Second Opium Wars and the Boxer Rebellion, Māori tribes in the first of the New Zealand Wars, Nawab Shiraj-ud-Daula's forces and British East India Company mutineers in the Sepoy Rebellion of 1857, the Boers in the first and second Boer Wars, Irish Fenians in Canada during the Fenian raids and Irish separatists in the Anglo-Irish War. The increasing demands of imperial expansion and the inadequacy and inefficiency of the underfunded British Army, Militia, Yeomanry and Volunteer Force after the Napoleonic Wars led to series of reforms following the failures of the Crimean War.