Hyderabad is the capital of the southern Indian state of Telangana and de jure capital of Andhra Pradesh. Occupying 650km2 along the banks of the Musi River, it has a population of about and a metropolitan population of about, making it the fourth most populous city and sixth most populous urban agglomeration in India. At an average altitude of 542m, much of Hyderabad is situated on hilly terrain around artificial lakes, including Hussain Sagar—predating the city's founding—north of the city centre.Established in 1591 by Muhammad Quli Qutb Shah, Hyderabad remained under the rule of the Qutb Shahi dynasty for nearly a century before the Mughals captured the region. In 1724, Mughal viceroy Asif Jah I declared his sovereignty and created his own dynasty, known as the Nizams of Hyderabad. The Nizam's dominions became a princely state during the British Raj, and remained so for, with the city serving as its capital. The city continued as the capital of Hyderabad State after it was brought into the Indian Union in 1948, and became the capital of Andhra Pradesh after the States Reorganisation Act, 1956. Since 1956, Rashtrapati Nilayam in the city has been the winter office of the President of India. In 2014, the newly formed state of Telangana split from Andhra Pradesh and the city became joint capital of the two states, a transitional arrangement scheduled to end by 2025.