Bahá'u'lláh, born Mírzá Ḥusayn-ʻAlí Núrí, was an Iranian religious leader and the founder of the Bahá'í Faith. Born to an aristocratic family in Iran, he was exiled due to his adherence to the messianic Bábism. In 1863, in Iraq, he declared his claim to a divine revelation and spent the rest of his life in further imprisonment in the Ottoman Empire.

His teachings revolved around principles of unity and religious renewal, ranging from moral and spiritual progress to world governance. Raised without formal education, Bahá'u'lláh was well-read and deeply religious. He declined a government position at age 22, choosing instead to manage family properties and donate to charities. At 27, he accepted the Báb's claim and became a prominent supporter of the new religious movement, which led to opposition and his eventual exile.

During imprisonment in the Síyáh-Chál dungeon, Bahá'u'lláh claimed to receive divine revelations, marking the start of his divine mission. Despite facing hostility and confinement, he continued to advocate his beliefs, eventually spending his final years in relative freedom near Acre.

Bahá'u'lláh authored over 1,500 letters, some book-length, translated into at least 802 languages. Notable works include the Hidden Words, the Kitáb-i-Íqán, and the Kitáb-i-Aqdas. He emphasized the mystical nature of God, the progress of the soul, societal needs, religious obligations, and the structure of Bahá’í institutions.

Bahá'ís regard him as a Manifestation of God, succeeding figures like Buddha, Jesus, or Muhammad. He viewed humans as spiritual beings and urged the development of divine virtues and societal advancement. Bahá'u'lláh died in 1892 near Acre, and his burial site remains a pilgrimage destination for Bahá’ís worldwide, now numbering between 5 and 8 million.