Mendel entered the Abbey of St. Thomas in 1843. The community provided a setting for teaching and study as well as religious duties. His principal pea experiments took place in 1856–1863. He presented the results in 1865 and published them in 1866. They belong to nineteenth-century science, after the eighteenth-century flourishing and suppression of many European religious houses.
He chose traits that could be distinguished clearly, controlled fertilisation and counted the offspring. The paper reports 5,474 round and 1,850 wrinkled seeds in the relevant generation. The ratio is close to three to one. Further breeding distinguished plants with the same outward appearance but different patterns in the following generation.
The strength of the argument lay in joining design, measurement and explanation. A casual resemblance between parents and offspring would not supply the same evidence. Nor did the later discovery of chromosomes have to be available before the numerical pattern could be established. Subsequent genetics explained and qualified how such patterns arise, including the conditions affecting independent assortment.
The abbey was part of the material and educational history of the work. That fact does not turn the experimental conclusion into a proposition deduced from theology. It establishes that religious vocation, institutional support and investigation of nature could coexist productively. Mendel’s example is precise enough to answer the blanket claim that monastic life made scientific discovery impossible.