The Siege of Mount Hiei (比叡山の戦い) was a battle of the Sengoku period of Japan fought between Oda Nobunaga and the sōhei (warrior monks) of the monasteries of Mount Hiei near Kyoto on 29 September 1571. Nobunaga and Akechi Mitsuhide led 30,000 men to Mount Hiei, destroying towns and temples on the mountain or near its base, and killing their residents without exemption. Nobunaga killed an estimated 20,000 people and around 300 buildings were burned to the ground, ending the great power of the Mount Hiei warrior monks.