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
In the aftermath of the Manicktala conspiracy, the western Anushilan Samiti found a more-prominent leader in Bagha Jatin and emerged as the Jugantar. Jatin revitalised links between the central organisation in Calcutta and its branches in Bengal, Bihar, Orissa and Uttar Pradesh, establishing hideouts in the Sunderbans for members who had gone underground. The group slowly reorganised, aided by Amarendra Chatterjee, Naren Bhattacharya and other younger leaders. Some of its younger members, including Taraknath Das, left India. Over the next two years, the organisation operated under the cover of two apparently-separate groups: Sramajeebi Samabaya (the Labourer's Cooperative) and Harry and Sons. Around this time Jatin began attempting to establish contacts with the 10th Jat Regiment, garrisoned at Fort William in Calcutta, and Narendra Nath committed a number of robberies to raise money. Shamsul Alam, a Bengal police officer preparing a conspiracy case against the group, was assassinated by Jatin associate Biren Dutta Gupta. His assassination led to the arrests which precipitated the Howrah-Sibpur Conspiracy case.