The story of pradal serey starts with the Khmer Empire. The Khmer Empire was founded in 802 A.D. at a time when many modern Southeast Asian countries didn't exist yet. Martial arts were used by the military of the Khmer Empire. Pradal Serey has its root from the hand-to-hand combat use by the military of the Khmer Empire. In the Angkor era, both armed and unarmed martial arts were practiced by the Khmers. Evidence shows that a style resembling pradal serey existed in the 9th century, which may be one of the reasons why the Khmer Empire was such a military powerhouse in Southeast Asia. The Khmer Empire used an early form of pradal serey along with various weapons and war elephants to wage war against their main enemy, the principalities of Champa.