In 1177, the Chams left their homeland (in what is now Southern Vietnam) and launched an invasion of the Khmer empire by ship. They sailed their boats up the Mekong River, across Tonle Sap lake, and then up the Siem Reap tributary to Angkor. They caught the Khmer by surprise and sacked the Khmer capital city, Yasodharapura, killing the Khmer king, Suryavarman II.
In 1178, a man named Jayavarman led the Khmer army in ousting the invaders. A former royal and military veteran, he brought the kingdom back together and was crowned as King Jayavarman VII in 1181. In 1190, he successfully led the campaign to conquer the Chams. He remains one of the most revered Kings of Angkor, building more than 17 temples during his reign, as well as the grand capital city of Angkor Thom.
Preah Khan was built in 1191 by Jayavarman VII on the site of his successful ousting of the Chams. It’s original name, Nagara Jayasri, means “Holy City of Victory”, and it’s current name, Preah Khan, is an interpretation of that, meaning “Holy Sword.” Jayavarman VII dedicated it to his father.
Preah Khan was a monastic complex, incorporating temples, a university, and even housing. Jayavarman VII himself even lived here while his home at Angkor Thom was being built. At its height, over 1,000 monks lived here, along with over 90,000 support staff. While the central shrine housed a Buddha, there were shrines for over 400 other deities throughout the complex.
Some anastylosis was carried out on Preah Khan in the 1930s, but it remains mostly unrestored. Banyan trees have taken over some of the main walls and buildings. And many other treasures are hidden behind collapsed walls and down darkened corridors.