- The Prarthana Samaj was established in 1867 in Bombay (now Mumbai) by Dadoba Pandurang and his brother Atmaram Pandurang. - Prominent leaders later associated with it included M.G. Ranade, R.G. Bhandarkar, and N.G. Chandavarkar. - Its main aims were social and religious reforms within Hinduism, such as opposition to caste system, advocacy for widow remarriage and female education, and promotion of monotheistic worship. - It was inspired by the Brahmo Samaj but focused more on social reform in Western India.