When Shah Jahan became ill in 1658, Dara Shikoh(who championed a syncretistic Hindu-Muslim culture and Mumtaz Mahal's eldest son) assumed the role of regent in his father's stead, which swiftly incurred the animosity of his brothers. Upon learning of his assumption of the regency, his younger brothers, Shuja, Viceroy of Bengal, and Murad Baksh, Viceroy of Gujarat, declared their independence and marched upon Agra in order to claim their riches. At the end of 1657, Dara Shikoh was appointed Governor of the province of Bihar and promoted to command of 60,000 infantry and 40,000 cavalry.