Girolamo Bernoulli’s origins are, inevitably, surrounded by the clutter of legend. None dared broach the subject after the Re-Formation, and he never discussed them. The folktales agree with each other as rarely as they match the historical record, and that occasional scholar courageous enough to eschew hagiography’s siren song is obliged to discard these several picturesque versions.2

The Engineers emerged in the last decades of the thirteenth century from a controversy soon forgotten,3 and the stage was clear for an actor of genius. The innocent lad we meet in the early thirteen twenties, dazzling the Curia’s preeminent Natural Philosophers with his mathematical gifts, is all but unrecognizable. While the man was solitary and secretive, the boy was noted for his friendships with the great theological and philosophical minds of the day. He cultivated many masters.4