Rattanakosin Kingdom (1782–1932)

The Rattanakosin Kingdom, also known as the Kingdom of Siam after 1855, refers to the Siamese kingdom (in modern-day Thailand) between 1782 and 1932. It was founded in 1782 with the establishment of Rattanakosin (Bangkok), which replaced the city of Thonburi as the capital of Siam. This article covers the period until the Siamese revolution of 1932.

The kingdom governed based on the mandala system. This allows for high-autonomy locally with the kingdom influencing and effectively ruling its area of suzerainty. At its zenith in 1805 to 1812, the Kingdom was composed of 25 polities, ranging from duchies and principalities to federations and kingdoms. With the furthest extent reaching the Shan States, southern Yunnan, Laos, Cambodia, northern Si Rat Malai and Kawthoung. The kingdom was founded by Rama I of the Chakri dynasty. The first half of this period was characterized by the consolidation of Siamese power in the center of Mainland Southeast Asia and was punctuated by contests and wars for regional supremacy with rival powers Burma and Vietnam. The second period was one of engagements with the colonial powers of Britain and France in which Siam remained the only Southeast Asian state to maintain its independence.

Internally, the kingdom developed into a centralized, absolutist, nation state with borders defined by interactions with Western powers. The period was marked by the increased centralization of the monarch's powers, the abolition of labor control, the transition to an agrarian economy, the expansion of control over distant tributary states, the creation of a monolithic national identity, and the emergence of an urban middle class. However, the failure to implement democratic reforms culminated in the Siamese revolution of 1932 and the establishment of a constitutional monarchy.