The founder of the `Brahmo Samaj` was Raja Ram Mohun Roy. The Brahmo Samaj was a socio-religious reform movement in India during the 19th century. Raja Ram Mohun Roy was a social and religious reformer who played a significant role in challenging and reforming traditional Hindu practices. He was a vocal advocate for abolition of practices like sati (widow immolation) and child marriage. He believed in monotheism and rejected idol worship, caste distinctions, and other beliefs associated with orthodox Hinduism. Raja Ram Mohun Roy`s efforts laid the foundation for the modern Brahmo Samaj, which aimed to promote rational thinking, social equality, and religious reform. He was also instrumental in the spread of modern education in India and worked towards the upliftment of women in society.