Rare autograph DS in German, signed "Gregor Mendel," one page, 8.25 x 13.5, September 1, 1876. Untranslated document concerning a financial transaction, issued from St. Thomas's Abbey in Brno. An official embossed red wax seal is affixed to the lower left, with two revenue stamps affixed near the top. Intersecting folds, light toning and soiling, and wrinkles to the upper right, otherwise fine condition.



When the young Johann Gregor Mendel entered the Augustinian St. Thomas's Abbey in Brno in the early 1840s, he commenced his training as a priest, taking the name Gregor and securing himself an education that would have otherwise been financially unattainable. Fascinated with heredity, he began studying mice, but at the behest of his bishop (who did not like the idea of his monks studying animal sex), quickly switched to plants. Conducting his studies in the monastery's five-acre experimental garden, he spent nearly two decades working with peas before developing his Law of Segregation and Law of Independent Assortment-which would later become Mendel's Laws of Inheritance.



Though his findings made little impact at the time of publication (1866), they would resurface 35 years later to become one of the biggest contributions to the emerging field of genetics. Becoming abbot of the monastery in 1868, Mendel left his scientific work behind to handle a lengthy dispute with the government regarding special taxes on religious institutions. Following his death, the succeeding abbot burned papers in Mendel's collection to mark an end to the financial troubles, making autographed material by the groundbreaking scientist very difficult to come by.