The other story refers to Galileo’s first mathematical studies. Gherardini relates that he was scarcely acquainted with the elements of mathematics up to his twentieth year, which, by the by, seems almost incredible. But while he was diligently studying medicine at Pisa, the court of Tuscany came there for some months. Among the suite was Ostilio Ricci, governor of the pages, a distinguished mathematician and an old friend of the Galilei family; Galileo, therefore, often visited him. One morning when he was there, Ricci was teaching the pages. Galileo stood shyly at the door of the schoolroom, listening attentively to the lesson; his interest grew greater and greater; he followed the demonstration of the mathematical propositions with bated breath. Strongly attracted by the science almost unknown to him before, as well as by Ricci’s method of instruction, he often returned, but always unobserved, and, Euclid in hand, drank deeply, from his uncomfortable concealment, of the streams of fresh knowledge. Mathematics also occupied the greater part of his time in the solitude of his study. But all this did not satisfy his thirst for knowledge. He longed to be himself taught by Ricci. At last he took courage, and, hesitatingly confessing his sins of curiosity to the astonished tutor, he besought him to unveil to him the further mysteries of mathematics, to which Ricci at once consented. When Galileo’s father learnt that his son was devoting himself to Euclid at the expense of Hippocrates and Galen, he did his utmost to divert him from this new, and as it seemed to him, unprofitable study. The science of mathematics was not then held in much esteem, as it led to nothing practical. Its use, as applied to the laws of nature, had scarcely begun to be recognised. But the world-wide mission for which Galileo’s genius destined him had been too imperiously marked out by fate for him to be held back by the mere will of any man. Old Vincenzo had to learn the unconquerable power of genius in young Galileo, and to submit to it. The son pursued the studies marked out for him by nature more zealously than ever, and at length obtained leave from his father to bid adieu to medicine and to devote himself exclusively to mathematics and physics.[16]