White Mughals by William Dalrymple

White Mughals is the romantic and ultimately tragic tale of a passionate love affair that crossed and transcended all the cultural, religious and political boundaries of its time. James Achilles Kirkpatrick was the British Resident at the court of the Nizam of Hyderabad when in 1798 he glimpsed Kahir un-Nissa—'Most excellent among Women'—the great-niece of the Nizam's Prime Minister and a descendant of the Prophet. Kirkpatrick had gone out to India as an ambitious soldier in the army of the East India Company, eager to make his name in the conquest and subjection of the subcontinent. Instead, he fell in love with Khair and overcame many obstacles to marry her—not least of which was the fact that she was locked away in purdah and engaged to a local nobleman. Eventually, while remaining Resident, Kirkpatrick converted to Islam, and according to Indian sources even became a double-agent working for the Hyderabadis against the East India Company.