Mind-Benders of Hindu History
A major reform movement born in a Bombay meeting in 1875
The ascetic Dayananda Saraswati (1824-1883) convened the first meeting of the Arya Samaj in Bombay on 10 April 1875, at the age of 51. The movement, which called for a return to the Vedas and campaigned against child marriage and for widow remarriage, became one of the most influential social-reform organizations of nineteenth-century India, and it endures today.
How we know
Arya Samaj founded 10 April 1875 in Bombay by Dayananda Saraswati (b. 1824, d. 30 Oct 1883); founder age 51; movement ~151 years old in 2026 (per Britannica and Wikipedia).
One of many fact-checked wonders across eight traditions at The Spring of Wisdom.