The 1841–1845 Siamese-Vietnamese War in Cambodia was a war between Vietnam (then under the rule of the Nguyen Dynasty) and Siam (Thailand) under the House of Chakkri. In the increasingly confrontational rivalry between Vietnam and Siam, the conflict was triggered by Vietnam's absorption of Cambodia and the demotion of the Khmer monarchs. Siam seized the opportunity to intervene as the tide of Khmer discontent rose against Vietnamese rule.