By the 11th-12th centuries, Mon Influenced over central Thailand.
Khmer cultural influence was brought in the form of language, art and religion.
The "Sanskrit" language was entered in Mon-Thai vocabulary during the Khmer or Lopburi Period. The influence of this period has affected many provinces in the north-east such as Kanchanaburi and Lopburi.
The Architecture in "Angkor" was also constructed according to the Khmers style.
The Khmer built stone temples in the northeast, some of which have been restored to their former glory, those at Phimai and Phanom Rung and further cultures are stone sculptures and stone Buddha images.
Politically, however, the Khmer cultural dominance did not control the whole area but power through vassals and governors.