What is the exact date of Gregor Mendel's birth?

Gregor Mendel was born on July 20, 1822.

His birthplace was Heinzendorf bei Odrau, a village in Austrian Silesia that is now called Hynčice and lies in the Czech Republic. He was born Johann Mendel; he later took the religious name Gregor when he joined the Augustinian order at St. Thomas’s Abbey in Brno.

A common mix-up gives July 22 as Mendel’s birth date. July 22 is often associated with his baptism in some older accounts, while July 20 is the accepted date of birth recorded in modern biographical references. Mendel later became an Augustinian friar, abbot, teacher, and pioneering experimenter in heredity.

His pea-plant experiments, conducted mainly between 1856 and 1863, established patterns now known as Mendelian inheritance. Although his work was initially overlooked, scientists rediscovered and confirmed its importance around 1900.