The Brahmo Samaj was a reform movement in India that emerged in the 19th century, with the aim of promoting monotheism and social reform. The founders of this movement were Raja Ram Mohan Roy and Debendranath Tagore.

Raja Ram Mohan Roy was a prominent social reformer and thinker who played a crucial role in the founding of the Brahmo Samaj. He was born in Bengal in 1772 and was a staunch advocate of social and religious reform. Roy was greatly influenced by the teachings of the Upanishads and believed in the concept of a universal religion based on the principles of reason and morality. He was also a strong advocate of women's rights and worked towards abolishing practices such as Sati and child marriage.

Debendranath Tagore, the father of the famous poet Rabindranath Tagore, was another key figure in the founding of the Brahmo Samaj. He was born in 1817 and was deeply influenced by the teachings of Raja Ram Mohan Roy. Tagore was a wealthy landowner and philanthropist who used his resources to promote social and religious reforms. He believed in the concept of a personal God and emphasized the importance of individual spiritual experience rather than ritualistic practices.

Together, Roy and Tagore founded the Brahmo Samaj in 1828 in Kolkata, with the aim of creating a society based on the principles of rationality, social equality, and monotheism. They rejected the traditional Hindu caste system and rituals, and instead, focused on the worship of a single God. The Brahmo Samaj also promoted the education of women and worked towards the eradication of social evils such as untouchability and child marriage.

The teachings of the Brahmo Samaj were further developed by Keshab Chandra Sen, who became a prominent leader of the movement in the late 19th century. Sen's ideas were more radical and he emphasized the importance of social service and the unity of all religions. He also advocated for the empowerment of women and the education of all members of society.

In conclusion, the Brahmo Samaj was founded by Raja Ram Mohan Roy and Debendranath Tagore, two influential social reformers who sought to promote monotheism and social reform in India. Their teachings and principles continue to influence modern-day Indian society and have played a significant role in shaping the country's religious and social landscape.