Gregor Mendel (Hynčice, Moravia, 1822 – Brno, 1884), an Augustinian friar at St. Thomas's Abbey in Brno, presents in 1865 to the Brno Natural History Society and publishes in 1866 his Versuche über Pflanzenhybriden, the result of eight years of experiments with 29,000 pea plants (Pisum sativum). He formulates the three laws of heredity — segregation, dominance, and independent assortment — that explain how traits are transmitted from parents to offspring in a discrete, predictable way. The article receives 115 citations between 1866 and 1900, none of which grasp its theoretical importance. Darwin, a contemporary and voracious reader of biology, never knew of Mendel's work. The article was simultaneously rediscovered in 1900 by De Vries, Correns, and Tschermak, 16 years after Mendel's death. Modern genetics is impossible without his laws, which articulate the mechanism of heredity that Darwin needed but did not have.