History of the Anushilan Samiti
Around 1902, Aurobindo Ghosh arranged for Bannerjee to return to Calcutta to begin organisational work, where he began a gymnasium and a youth society. It was at this time that Bannerjee came in touch with Vibhuti Bhushan Bhattacharya, Sarala Devi Ghoshal and Pramathanath Mitra. In Calcutta, a few clubs and societies were still active at the time. Most notable was a gymnasium in Ballygunge Circular Road run by Sarala Devi herself, a second was an organisation named "Anushilan Samiti" founded by Satish Chandra Basu with the patronage of Pramathanath Mitra. A third one was a youth club called "Attōnnōti Samiti" (Self-improvement society) in central Calcutta.
Anushilan Samiti
Anushilan established early links with foreign movements and Indian nationalists abroad. In 1907 Barin Ghosh sent Hem Chandra Kanungo (Hem Chandra Das) to Paris to learn bomb-making from Nicholas Safranski, a Russian revolutionary in exile. Paris was also home to Madam Cama, amongst the leading figures of the Paris Indian Society and India House in London. A bomb-making manual later found its way through V.D. Savarkar to the press at India House for publication. In 1908, young recruits Khudiram Bose and Prafulla Chaki were sent on a mission to Muzaffarpur to assassinate chief presidency magistrate D. H. Kingsford. They bombed a carriage they mistook for Kingsford's, killing two Englishwomen. In the aftermath of the bombing, Bose was arrested while attempting to flee and Chaki committed suicide. Police investigation of the killings revealed the organisation's quarters at Barin's country house in Manicktala (a suburb of Calcutta) and led to a number of arrests, including Aurobindo and Barin. The ensuing trial, held under tight security, led to a death sentence for Barin (later commuted to life imprisonment); others went underground. The case against Aurobindo Ghosh collapsed after the assassination of Naren Gosain, who had turned crown witness. Gosain was shot in Alipore jail by Satyendranath Basu and Kanailal Dutta, who were also being tried. Aurobindo retired from active politics after being acquitted. This was followed by a 1909 Dhaka conspiracy case, which brought 44 members of the Dhaka Anushilan to trial. Nandalal Bannerjee (the officer who arrested Kshudiram) was shot dead in 1908, followed by the assassinations of the prosecutor and informant for the Alipore case in 1909.