It grew out of the Chen-La in 802
This empire absorbed territories formerly of the Dvaravati civilization, especially Phamai and Lopburi, which it conquered following a war with the Mon kingdom of Harinjaya. It grew out of the Chen-La in 802 and it was centered on the Khorat Plateau, extending as far south as Nakhon Si Thammarat. This empire met its end after its capital was invaded by Ayutthaya in 1431, but its height came three centuries earlier under rulers like Suryavarman II and Jayavarman VII. For 10 points, name this empire that constructed the temple complex at Angkor Wat, a Cambodian empire which lent its name to a Communist party led by Pol Pot. 
This empire absorbed territories formerly of the Dvaravati civilization, especially Phamai and Lopburi, which it conquered following a war with the Mon kingdom of Harinjaya.
Khmer Empire [accept Angkor Empire or Angkoran Empire, before "Angkor Wat"]Â 