The Prarthana Samaj (Prayer Society) was founded on 31 March 1867 in Bombay (now Mumbai), which is in Maharashtra. It was established by Atmaram Pandurang, with later prominent leaders including Mahadev Govind Ranade and R. G. Bhandarkar. The Samaj aimed at rational worship of one God and social reform, drawing inspiration from the Brahmo Samaj in Bengal but primarily focusing on devotional activities and social service.