Most of the Rajput states, since the reign of Akbar, had been close allies of the Mughals. However, when Mughal power began to decline, they became independent and tried to increase the boundaries of their kingdoms. The most outstanding Rajput ruler of this period was Sawai Raja Jai Singh of Amber (later called Jaipur). He was a man of science in an age when the Indians were unaware of het scientific achievements of the West. He founded the city of Jaipur and built astronomical observatories at Delhi, Jaipur, Mathur, Ujjain and Benaras.