The Communist Party of Thailand (Abrv: CPT; , ) was a communist party in Thailand active from 1942 until the 1990s. Initially known as the Communist Party of Siam, the party was founded officially on 1 December 1942, although communist activism in the country began as early as 1927. In the 1960s, the CPT grew in membership and support and by the early 1970s was the second largest communist movement in mainland Southeast Asia (after Vietnam). The party launched a guerrilla war against the Thai government in 1965. Even though the CPT suffered internal divisions, at its political peak the party effectively acted as a state within the state. Its rural support is estimated to have been at least four million people; its military arm consisted of 10–14,000 armed fighters. Its influence was concentrated in the northeastern, northern and southern Thailand. Following a series of internal party disputes, changes in international communist alliances, successful counter-insurgency policies of Thailand's government including a widely accepted offer of amnesty for party cadres, and the Cold War coming to its conclusion, the party disappeared from the political scene in the early-1990s. 1920s–1930s The origins of the communist movement in Thailand begin with the founding of the Siam Special Committee of the South Seas Communist Party between 1926 and 1927. An infusion of leftists fleeing China for Thailand in the late 1920s following the Nationalist-Communist split of 1927 also increased support for activities. Accounts vary, but sometime between late 1929 and early 1930 the Communist Party of Siam was inaugurated. 1940s–1950s: Party creation During its initial phase of existence, the Communist Party of Siam remained a small party. It mainly comprised intellectuals in Bangkok. By early-1948, British intelligence sources deemed reports that the party had 3,000 members nationwide as "exaggerated". The party enjoyed a brief period of legality from 1946 to 1948. The secret party headquarters were in a wooden building on Si Phraya Road, Bangkok. A CPT delegation attended the second national congress of the Communist Party of Vietnam (CPV) in Tuyen Quang in February 1951. The CPT held its second party congress in 1952. 1960s: The People's War In 1960, the party attended the International Meeting of Communist and Workers Parties held in Moscow. The CPT held its third party congress in September 1961. In the Sino-Soviet split, the CPT sided with the Communist Party of China. In October 1964, its position was