Key Facts
- Period
- 1431–1863
- Duration
- ~432 years
- Siamese conquest of Longvek
- 1594
- French Protectorate established
- 11 August 1863
- Primary capitals
- Angkor Thom, Phnom Penh, Longvek
Imperial Zenith Metrics
Historical Trajectory
Phase I: Rise
Following a Siamese intervention at Angkor Thom around 1431, Cambodia's political centre shifted southward toward the river port region of Phnom Penh and later Longvek. This transition marked the end of the classical Angkor era, with stone temple construction already having ceased after Jayavarman VII's reign and royal chronicles becoming increasingly sparse through the 14th and 15th centuries.
Phase II: Zenith
During the 16th century, the capital Longvek on the Mekong prospered as part of the Asian maritime trade network, facilitating Cambodia's first contacts with European explorers. The kingdom engaged in regional commerce and maintained a degree of independence, though it faced persistent rivalry with the Ayutthaya Kingdom to the west and expanding Vietnamese influence to the southeast.
Phase III: Decline
Siamese and Vietnamese dominance intensified through the 17th and 18th centuries, reducing Khmer monarchs to vassal status and forcing frequent relocations of the capital. By the mid-19th century Cambodia was placed under joint Siamese-Vietnamese suzerainty, losing national sovereignty. King Ang Duong and his successor Norodom Prohmbarirak ultimately accepted French protection, formalised on 11 August 1863, to prevent absorption by either neighbour.
Notable Imperial Reigns
Selected rulers mapping the empire’s trajectory