The ancient history of Kathmandu is described in its traditional myths and legends. According to Swayambhu Purana, present-day Kathmandu was once a huge and deep lake named "Nagdaha", as it was full of snakes. The lake was cut drained by Bodhisatwa Manjushree with his sword, and the water was evacuated out from there. He then established a city called Manjupattan, and made Dharmakar the ruler of the valley land. After some time, a demon named Banasur closed the outlet, and the valley again turned into a lake. Then Lord Krishna came to Nepal, killed Banasur, and again drained out the water. He brought some Gopals along with him and made Bhuktaman the king of Nepal.