Anushilan Samiti
By 1902, Calcutta had three secret societies working toward the violent overthrow of British rule in India. One was founded by Calcutta student Satish Chandra Basu with the patronage of Calcutta barrister Pramatha Mitra, another was led by Bengali woman Sarala Devi and the third was founded by Aurobindo Ghosh. Ghosh was one of the strongest proponents of militant Indian nationalism at the time. By 1905 the work of Aurobindo and his brother, Barin, enabled Anushilan Samity to spread throughout Bengal. Nationalist writings and publications by Aurobindo and Barin, including "Bande Mataram" and "Jugantar", had a widespread influence on Bengal youth. The 1905 partition of Bengal stimulated radical nationalist sentiments in Bengal's Bhadralok community, helping Anushilan acquire a support base of educated, politically-conscious and disaffected members of local youth societies. Its program emphasized physical training, training its recruits with daggers and "lathis" (bamboo staffs used as weapons). The Dhaka branch of Anushilan was led by Pulin Behari Das, and branches spread throughout East Bengal and Assam. More than 500 branches were opened in eastern Bengal and Assam, linked by "close and detailed organization" to Pulin's headquarters at Dhaka. It absorbed smaller groups in the province, soon overshadowing its parent organisation in Calcutta. Branches of Dhaka Anushilan emerged in Jessore, Khulna, Faridpur, Rajnagar, Rajendrapur, Mohanpur, Barvali and Bakarganj. Estimates of Dhaka Anushilan Samiti's reach indicate a membership of 15,000 to 20,000. Within two years, Dhaka Anushilan devolved its aims from the Swadeshi to that of political terrorism.
Anushilan Samiti
Through the 1920s and 1930s, many Anushilan members began identifying with Communism and leftist ideologies. Many of them studying Marxist–Leninist literature whilst serving long jail sentences. A minority section broke away from the Anushilan movement and joined the Communist Consolidation, and later the Communist Party of India. Former Jugantar leader Narendranath Bhattacharya, now known as M. N. Roy, became an influential member of the Communist International, helping to find the Communist Party of India. The majority of the Anushilanite Marxists, whilst having adopted Marxist–Leninist thinking, felt hesitant over joining the Communist Party. Holding sharp differences with the CPI and Royist ideologies, the Anushilan marxists decided to join Congress Socialist Party (CSP), but keeping a separate identity within the party. The RSP, which derived from the "Samiti", held a strong influence in parts of Bengal. The psrty sent two parliamentarians in the 1952 Lok Sabha elections, both previously "Samiti" members. In 1969 RSP sympathizers in East Pakistan formed the Shramik Krishak Samajbadi Dal (SKSD). RSP and SKSD have maintained close ties since. The RSP is a minor partner in the Left Front which ruled the Indian state of West Bengal for 34 uninterrupted years. It also holds influence in South India, notably in parts of Kerala. The SUCI, another left wing party with a presence in Bengal, was founded in 1948 by Anushilan members.