King of the Khyber Rifles (1916) by

King of the Khyber Rifles is a novel by British writer Talbot Mundy. Captain Athelstan King is a secret agent for the British Raj at the beginning of the First World War. Heavily influenced both by Mundy's own unsuccessful career in India and by his interest in theosophy, it describes King's adventures among the (mostly Muslim) tribes of the north with the mystical woman adventuress, princess Yasmini and the Turkish mullah Muhammed Anim. Like Greenmantle by John Buchan, also first published in 1916, it deals with the possibility that Turkey might try to stir Muslims into a jihad against the British Empire.