The Brahmo Samaj, literally the "Society of Brahma", was founded as a movement by Ram Mohan Roy. In 1850 Roy's successor Debendranath Tagore broke from Hinduism and created the new religion of Brahmoism which was recognised as a religion distinct from Hinduism by the Privy Council in 1901, and by the Law Commission of Bangladesh in 2001.
On God: There is always Infinite (limitless, un-definable, imperceivable, indivisible) Singularity - immanent and transcendent Singular Author and Preserver of Existence - "He" whose Love is manifest everywhere and in everything, in the fire and in the water, in the smallest plant to the mightiest oak.
On Being: Being is created from Singularity. Being is renewed to Singularity. Being exists to be one (again) with Loving Singularity. (See Tat Tvam Asi.)
On Intelligent Existence: Righteous (worshipful, intelligent, moral) actions alone rule (regulate [preserve]) Existence against Chaos (loss [decay, return, pervading emptiness]). Knowledge (Intelligence [reason, sentience, intuition]) of pure Conscience (light within) is the One (Supreme) ruler (authority [law, dharma]) of Existence with no symbol (creation [scripture, book, object]) or intermediary (being [teacher, messiah, ruler]).
On Love: Respect all creations and beings but never venerate (worship) them for only Singularity can be loved (adored, worshipped).
Brahmos embrace righteousness as the only way of life.
Brahmos embrace truth, knowledge, reason, free will and virtuous intuition (observation) as guides.
Brahmos embrace secular principles but oppose sectarianism and imposition of religious belief into governance (especially propagation of religious belief by government).
Brahmos embrace the co-existence of Brahmo principles with governance, but oppose all governance in conflict with Brahmo principles.
Brahmos reject narrow theism (especially polytheism), idolatry and symbolism.
Brahmos reject the need for formal rituals, priests or places (church, temple, mosque) for worship.
Brahmos reject dogma and superstition.
Brahmos reject scriptures as authority.
Brahmos reject revelations, prophets, gurus, messiahs, or avatars as authority.
Brahmos reject bigotry and irrational distinctions like caste, creed, colour, race, religion which divide beings.
Brahmos reject all forms of totalitarianism.
Brahmos examine the prevalent notion of "sin".
Brahmos examine the prevalent notions of "heaven" or "hell".
Brahmos examine the prevalent notion of "salvation".
Adherence to these articles are required only of Adi Brahmos or such Sadharan Brahmos who accept Adi-ism i.e. Trust deed of Brahmo Sabha (1830).
While Ram Mohan Roy aimed at reforming Hinduism from within, his successor Maharshi Debendranath Tagore in 1850 rejected the authority of the Vedas and thus broke with orthodox Hinduism. Tagore tried to retain some Hindu customs, but a series of schisms eventually resulted in the formation of the breakaway Sadharan Brahmo Samaj in 1878 based on Christian practices and dogmas.
So, in 1901, a decision of the Privy Council of British India found that "the vast majority of Brahmo religionists are not Hindus and have their own religion".
The Brahma Dharma was first codified by Debendranath Tagore with the formulation of the Brahmo Dharma Beej and publication of the Brahma Dharma, a book of 1848 or 1850 in two parts. The Brahma Dharma is the source of every Brahmo's spiritual faith and reflects Brahmo repudiation of the Hindu Vedas as authority and the shift away from Ram Mohan Roy's Vedantic Unitary God per the Adi Shankara Advaita school. The traditional seed principles and Debendranath's Brahmo Dharma (or religious and moral law) now stand evolved as the "Fundamental Principles of Brahmoism" and are supplemented by precise evolving rules for adherents, akin to "Articles of Faith" which regulate the Brahmo way of life. In addition the assembly of Brahmos (and also Brahmo Samajists) for meeting or worship is always consonant with the Trust Principles of 1830 or its derivatives.
1830 : Dwarkanath Tagore, Prasanna Coomar Tagore and Ors. establish the first Brahmo Place for Worship through a legal Trust Deed at Chitpur (JorasankoKolkataIndia). Ram Mohun departs for Britain.
1833 : Ram Mohun dies in Bristol.
1839 : Debendranath Tagore forms Tattwabodhini (@Tattvaranjini) Sabha, the "Truth & Life Purpose Seekers" association on October 6, 1839.
1843 : Tattwabodini Sabha merged with Brahmo Sabha  and Calcutta Brahmo Samaj established. Dwarkanath Tagore founds the Great Western Bengal Railway Co. in conflict with the State.
1850 : Publication of Brahma Dharma book in 2 parts by Debendranath. Repudiation of Vedic infallibility, separation from Hinduism, establishment of the new religion.
1855 : Keshub Chunder Sen founds "The British India Society" later associated with Christian missionariesJames Long and Charles Dall. Dall, a roving Unitarian missionary, is in a troubled marriage in Boston with female emancipator Caroline Wells Healey Dall, suffering a series of mental depressions, and is sufficiently persuaded to grant his wife a Boston divorce by sailing to India forever as the first foreign Unitarian missionary.
1856 : Devendranath Thakur proceeds to hills of Simla.
1857 : Debendranath informs Unitarian preacher Charles Dall that he is no longer welcome at Calcutta Brahmo Samaj, and that "he would not hear the name of Jesus spoken in the Samaj". Dall then forms the Rammohun Roy Society to wean away the liberal Brahmos from Debendranath. Keshub Sen then subscribes to Calcutta Brahmo Samaj while Devendranath is away in Simla. The Indian Mutiny erupts, almost every Trustee of Brahma Samaj supports the Crown while seeking exemplary punishment for the mutineers.
1860 : Charles Dall now openly attacks Debendranath and affiliates to liberal Brahmo neo-Christian group by promoting Theodore Parker and William Channing's methods to convert Hindus to Christianity.
1866 : The First Brahmo Schism and Calcutta Brahmo Samaj is renamed as Adi (First) Brahmo Samaj to distinguish it from progressive breakaway group.
1871 : Adi Brahmo Samaj leaders publicly oppose the progressive faction over the divisive Brahmo Marriage Bill, 1871 with Debendranath stating "We are Brahmos first, and Indians or Hindus second."
1872 : The Marriage Bill is ostensibly not limited to Brahmos and enacted as the Special Marriages Act (Act III) of 1872. A declaration is required stating "I am not a Hindu or Muslim or Christian or Jew" to marry under this law which is used almost exclusively by Brahmos.
1878 : The breakaway faction splits again, the majority form the middle-path Sadharan (General) Brahmo Samaj and are formally welcomed back to Brahmoism by Debendranath Tagore and Rajnarayan Basu of the Adi Samaj. The eminent leaders of Sadharan Brahmo Samaj at the time include Sivanath Sastri, Ananda Mohan Bose and Sib Chandra Deb.
1898 : First branch of Brahmosamaj (At Calicut) (Now Ayathan School which runs under the patronage of Brahmosamaj at Jail road, Calicut))was founded by Ayyathan Gopalan a great social reformer and founder of Sugunavardhini movement in Kerala.
^Official website [www.brahmosamaj.in] "In 1901 (Bhagwan Koer & Ors v J.C.Bose & Ors, 31 Cal 11, 30 ELR IA 249) the Privy Council (Britain's highest judicial authority) upholds the finding of the High Court of the Punjab that the vast majority of Brahmo religionists are not Hindus and have their own religion"