Kulin Brahmin is the highest strata of upper caste Brahmins in India's caste system. This term is more generally used to refer to upper caste "twice-born" Brahmins in nineteenth century Bengal considered themselves to be more knowledgeable as regards the scriptures as compared to other Brahmins.
The Brahmo Samaj originated to remove the evils of Kulin Brahminism like polygamy and sati (wherein widows were burnt alive to grab their share in undivided property). From 1822, over 500 secular Kulin Brahmins of Calcutta organised themselves into a vigilante force under legal experts like Ram Mohan Roy, Dwarkanath Tagore and Prasanna Coomar Tagore known as the Brahma Sabha to report and prosecute such offences. A counter force called Dharma Sabha was quickly formed by another set of orthodox Hindu Kulins to excommunicate Brahmins of the Brahma Sabha or assassinate them. Finally in 1829 the Governor General William Bentinck outlawed sati. The excommunicated Brahmins formed their own religion Brahmoism the following year 1830 which was finally codified in 1850, and recognised by the British Government in 1872, and by the Supreme Courts in 1903.