The evolution of the Kingdom of Siam in relation to the Khmer Empire: rivalries and cross-influences
- Editorial team
- Aug 6
- 2 min read
Updated: Aug 7
The history of the Kingdom of Siam (now Thailand) is deeply linked to that of the Khmer Empire, both through a dynamic of military confrontation and through an extraordinary cultural and institutional heritage. Their shared evolution has helped shape the identity and geopolitics of the entire continental region of Southeast Asia.
From their origins to coexistence under Khmer influence
In the beginning, the ancestors of the Thai people came from southern China and settled in regions that were part of the sphere of influence of the powerful Khmer Empire. Until the 13th century, the Mekong Basin and the Chao Phraya Valley were dominated by the administrative organisation, culture and religion of the Khmer civilisation.
The Thais adopted many Khmer elements: centralised administration, monumental architecture, writing (with the Thai alphabet largely inspired by ancient Khmer) and, above all, Theravada Buddhism, which gradually became the dominant religion in Siam after passing through the Mon and Khmer peoples.
Siamese affirmation and conquests
In the 13th century, the gradual decline of the Khmer Empire led to the emergence of new Thai kingdoms, such as Sukhothai and then Ayutthaya (founded in 1350). Although these new powers were inspired by the Khmer model, they also sought to surpass its authority:
In 1431, the Ayutthaya army captured Angkor, the Khmer capital, marking the beginning of the irreversible decline of medieval Cambodia.
Ayutthaya absorbed former Khmer territories and imposed military and economic domination over parts of Cambodia, leading to the occasional vassalage of the Khmer kingdom.
Mutual exchanges and resistance
This regional domination was not just a succession of conflicts: it was accompanied by an intense exchange of know-how, rituals and craftsmen. Many Thai temples from the Ayutthaya period inherited Khmer architectural techniques. Conversely, surviving Cambodian rulers sometimes settled at the Siamese court, drawing on its administrative and ceremonial models.
The 16th and 17th centuries saw Siam play the role of both ally and rival to Cambodia, which was then torn between Siamese and Vietnamese intervention.
The Khmer legacy in Siamese identity
Over the centuries, Siam developed its own identity, but its institutional, religious and artistic foundations remained deeply marked by the former Khmer empire. Royal myths, the state religion, place names and Thai urban planning betray this connection. Modern Thailand still draws on this rich heritage, while the memory of its struggles and alliances with Cambodia remains a strong marker of regional historical consciousness.
In short, the Kingdom of Siam, born and raised in the shadow of the Khmer Empire, established itself, through conquest and adaptation, as a pivotal power in Southeast Asia.