The kingdom under King Adityaraja, came into conflict with the Khmers in the twelfth century. Lamphun inscriptions from 1213, 1218, and 1219, mention King Sabbadhisiddhi endowing Buddhist monuments.[1]:195
The chronicles say that the Khmer unsuccessfully besieged Hariphunchai several times during the 11th century. It is not clear if the chronicles describe actual or legendary events, but the other Dvaravati Mon kingdoms did in fact fall to the Khmers at this time. The early 13th century was a golden time for Hariphunchai, as the chronicles talk only about religious activities or constructing buildings, not about wars. Nevertheless, Hariphunchai was besieged in 1292 by the Lanna king Mangrai the Great, who incorporated it into his Lan Na ("One Million Rice Fields") kingdom