What was Mendel's original given name at birth?

Gregor Mendel’s original given name at birth was Johann.

He was born Johann Mendel on July 20, 1822, in Heinzendorf, in Austrian Silesia, an area now known as Hynčice in the Czech Republic. He came from a German-speaking farming family and initially grew up helping with agricultural work.

When Mendel entered the Augustinian Order at St. Thomas’s Abbey in Brno, he received the religious name Gregor, derived from the Latin Gregorius. He later became widely known as Gregor Johann Mendel, which can make “Gregor” appear to have been his birth name.

A related historical detail is that Mendel’s monastic career helped him pursue education and research. His pea experiments, conducted mainly between 1856 and 1863, eventually established principles now known as Mendelian inheritance. His work was published in 1866 but received broad recognition only after its rediscovery around 1900.