The Rattanakosin Kingdom (, , , abbreviated as , ), the Kingdom of Siam, or the Early Bangkok Empire (1767-1851), were names used to reference the fourth and current Thai kingdom in the history of Thailand (then known as Siam). 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 maximum zone of influence of Rattanakosin included the vassal states of Cambodia, Laos, Shan States, and the northern Malay states. 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. History Early Rattanakosin period (1782–1855) Foundation of Bangkok Chakri ruled under the name Ramathibodi, but was generally known as King Rama I, moved the royal seat from Thonburi on the West bank of Chao Phraya River to the East bank, the village of Bang Makok, meaning "place of olive plums", for better strategic position in defenses against Burmese invasions from the West, protected from attack by the river to the west and by a series of canals to the north, east and south. The East bank was low marshlands inhabited by the Chinese, whom King Rama I ordered to move to Sampheng. The official foundation date of Bangkok was April 21, 1782 when the city pillar was consecrated in a ceremony. King Rama I underwent an abbreviated form of coronation in 1782. He founded the Chakri dynasty and made his younger brother Chao Phraya Surasi