Gregor Mendel (1822-1884), an ethnic German, was born in Austrian Silesia, Austrian Empire, nowadays Hyncice, Czech Republic. Johann Mendel, he took the name Gregor when entering the monastery, worked as a gardener and cultivated bees before entering the Philosophical Institute of Olomouc between 1840-43. His physics teacher recommended him to the Augustinian Abbey of Saint Thomas in Brno 1843 (Catholic). 1851 he went to the University of Vienna to study and returned to the monastery 1853 as a teacher mainly in physics.
He was encouraged by his university teachers and by colleagues at the monastery to study the variation of plants. Between 1856 to 1863 Mendel used some 29,000 pea plants in the monastery garden and deduced The Law of Segregation, i.e., the dominant and recessive distribution of 3:1 and The Law of Independent Assortment, i.e., traits vary independently of each other. He published these results in 1865.
Charles Darwin published his book Origin of Species 1859 and is said to have received a book of the 40 Mendel had printed, although another source claimed he did not know of the data. It is fascinating how the study of a natural phenomenon can lead to the discovery of a natural law. Genes had been found although they were not yet called as such. At the time most biologists held the belief of blending inheritance and Charles Darwin's attempt to explain inheritance with the theory of pangenesis was unsuccessful.
At the time Mendel did not get any response from his work from other scientists. He became abbot in 1868 and became an administrator. It was not until 1900 when his work was independently rediscovered by three scientists, Hugo de Vries, Carl Correns and Erich von Tschermak, that the field finally developed. Around 1936-47 evolution fused with genetics called the 'modern synthesis'.
Data from Wikipedia and New World Encyclopedia