A few notes on Mendel the man, to flesh out what's been written about his work.
Student
Mendel was born in Silesia, north of Moravia, to a poor farming family. (The town, called Heizendorf while Silesia was under German occupation, is now called Hynčice.) Young Johann Mendel -- Gregor was the name he took when he became a monk -- had two sisters and no brothers, and should have been the one to take over the farm when his father Anton was crippled by a falling tree. But he was sickly and neurasthenic, hardly a robust farmhand. Nobody knew for certain what was wrong with him, but it was clear that he was only cut out for studying. But his family was struggling because of his father's injury, and Johann had to put himself through school with tutoring jobs. His sister Theresia ended up loaning him her dowry money so he could attend the Philosophical Institute in Olomouc, but even then he ran out of funds. To continue learning, he would have to sign on with the Augustinian monks.
Monk
The monastery Mendel joined was headed by Abbott Cyrill Napp. Mendel was accepted on the recommendation of his physics teacher from the Philosophical Institute, who called him "almost the best" among his students -- Johann must have seemed bright but not entirely extraordinary. Abbott Napp was filling the Brünn monastery with scholars -- their motto was per scientiam ad sapientiam, from knowledge to wisdom. It seemed the perfect place for a boy too weak to work and too poor for school.
Mendel advanced quickly at the monastery, though this was more because they were running low on priests than because of any merit on his part. He was ordained only fifteen days after he turned 25 (minimum age for a priest). However, he was too weak or too compassionate to minister to the ill, as was expected of a parish priest. He took to his bed, as he had in his childhood and his school years. He was obviously no more suited to tending his infirm flock than he had been to farming. Abbott Napp decided that perhaps he'd make a better teacher.
Teacher
Mendel was, in fact, a good teacher, contagiously enthusiastic and generally beloved of his students. However, he was never able to pass the teaching exams. Whatever caused his long spells of fatigue perhaps also contributed to his test anxiety. When asked, in a zoology essay for the teaching exams, for the classifications of mammals and their uses to man, he forgot all his scientific terminology, listing the orders as "quadrumana," "quadrupeds," "plantigrades," clawed ungulates," "hoofed ungulates," and "web-footed animals etc." To describe why hoofed ungulates were useful to humans, the man who would be the father of genetics wrote:
the horse;
the ass;
the ox;
the sheep;
the goat;
the chamois, the deer, and the stag;
the llama, much used in Mexico as a beast of burden carrying light loads up to one or two hundredweight;
the musk ox;
the reindeer;
what the reindeer is for the north, the camel is for the hot steppes;
the pig;
the elephant is a splendid beast of burden.
Small wonder that, even after being sent to the
University of Vienna to study with the likes of
Christian Doppler and
Felix Unger, Mendel never passed his exams.
Experimenter
His repeated failures with his examinations drove Mendel to his bed once again. This time, when he arose, it was to begin the experiments with Pisum sativum that would (eventually) make his name. Abbott Napp built him a greenhouse for his experiments (and for the monastery's vegetables, including Mendel's favorite, cucumbers). He also set up a little sanctuary in the orangery, where he would count endless pods and flowers and seeds.
There is some assertion that Mendel faked his results. This is unlikely; it's more likely that he fudged them somewhat, that when he encountered a pea that wasn't (for instance) definitively wrinkled or round, he counted it in the group that best fit the ratio. And his results were suspiciously perfect, but at the same time, Mendel was meticulous with his pea plants. He encased each flower in a little calico bag, to prevent accidental cross-pollination or self-pollination, and would then visit each plant playing fertilization fairy, taking out a few pollen grains at a time with his camel-hair brush and transferring them to another plant's flower. If anyone could get near-perfect ratios, it would be super-scrupulous Father Gregor. (He even called his pea plants his "children," so careful was he of their welfare.)
Mendel's first presentation of the paper about his Pisum experiments (which had taken him years) was not well-received, to say the least. He presented the paper in two parts, on February 8 and March 8, 1865, and on both occasions, the members of the Brünn Society for the Study of Natural Sciences were bewildered and nonplussed. They didn't fully understand what he was talking about, and certainly didn't think it had any particular significance. With characteristic earnestness, Mendel nevertheless sent his paper to several prominent scientists, including Charles Darwin. Most went unread; Darwin's copy, reportedly, was found with uncut pages. The only one to respond was Karl Nägeli, and he (deliberately or accidentally) sabotaged Mendel's experiments by suggesting that he replicate them with Nägeli's own favorite plant, the hawkweed (Hieracium). Hawkweed reproduce asexually; unsurprisingly, then, Mendel was never able to reproduce his results, and became somewhat disillusioned. Still, the wall of the Mendel Museum in the former Brünn (now called Brno) bears his supposed rejoinder to these rejections: Má Doba Přjide, my time will come. (Mendel would have said "Meine Zeit wird schon kommen," but Brno is now Czech-speaking through and through.)
Prelate
As Mendel's attempts to cross-breed hawkweed trickled off, his duties as the new abbott took over. Shut out from the intellectual elite, he immersed himself in monastery business. This time, he did not have to react to his disappointment by falling ill; he was already semi-bedridden, suffering from edema, Bright's disease, and encroaching obesity. Nevertheless, he played skittles and chess, tended the monastery's bees, bred fuschia, and managed to be an inveterate practical joker -- one story holds that he impishly convinced a young monk to lay his biretta on the ground by the hives, at which point the hat immediately went from black to yellow. As Mendel delicately put it, the bees "used it as a site on which to void that which, for reasons of cleanliness, they had refrained from voiding in the hives during the winter." But although he kept his spirits after the latest string of disappointments, Mendel did not pursue his experiments. By the time the glasshouse was destroyed in a freak tornado in 1870, Mendel's breeding techniques had been relegated to gardening tips.
Genius
Mendel died on January 6, 1884, without knowing that his experiments would come to anything. His work was not rediscovered for almost thirty years. Eventually, however, this shy scamp of a priest would teach more than his third-grade mathematics classes. Through his rediscoverers, he showed science what Darwinism had been missing: the mechanism of heredity and of evolution.
Henig, Robin Marantz. The Monk in the Garden. New York: Houghton Mifflin, 2000.
Czech speakers: I'm quoting the legend on the museum wall from memory... if my accent marks are wrong please let me know