Political history of Sri Aurobindo
Anushilan Samiti was founded as an attempt to organize Bengali youth through a program of physical fitness and spiritual training for a nationalist program. By 1902, Calcutta had three societies working under the umbrella of Anushilan Samity, a society earlier founded by a Calcutta barrister by the name of Pramatha Mitra. These included Mitra's own group, another led by a Bengali lady by the name of Sarala Devi, and a third one led by Aurobindo Ghosh. The Anushilan Samiti had Aurobindo and Deshabandhu Chittaranjan Das as the vice-presidents, Suren Tagore the treasurer. Jatindra Nath Banerjee (Niralamba Swami), Bagha Jatin, Bhupendra Nath Datta (Swami Vivekananda's brother), Barindra Ghosh were among other initial leaders.
By 1905, the work of Aurobindo and his brother Barin Ghosh allowed Anushilan Samity to spread through Bengal.
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.