Leonardo’s patron, Giuliano de’ Medici, had been appointed governor of this particular area and, since Pope Leo X was fearful of two powerful countries, France and Spain, he was preparing the papal territory against possible invasion. Another fear of the Pope—and indeed of everybody in Rome—was malaria, the disease carried by the mosquitoes that bred in the Pontine marshes west and southwest of the city. At that time, however, no one knew the cause was mosquitoes; rather, they thought it was the bad air from the marshes. As Leonardo had already been effective in draining the pestilential marshes of Piombino for Cesare Borgia and, later, those around Milan for Charles d’Amboise, he was assigned the same task for the Pontine marshes. He surveyed the entire area to the sea and made another extraordinary aerial type map. His recommendations included draining the entire area, enlarging and regulating the Martino river and cutting an extra outlet from the river Livoli to the sea. These plans were adopted some years later and parts of the marshes were drained successfully, yielding new land for the cultivation of crops. By December of 1514 Leonardo had finished his treatise on speech and, possibly in an effort to attract the attention of the Pope, he submitted it to the Privy-Chamberlain, Battista dell’Aquila. As Pope Leo was surrounded by an army of secretaries and assistants who passed on everything submitted, this manuscript with its beautiful drawings was mislaid and lost and only a few notes and sketches remain. The continual discouragement of his life in Rome was offset by a visit from his half-brother, Giuliano, around Christmas. Leonardo was held in esteem by his family despite the quarrel over his father’s and his uncle Francesco’s will, and his half-brothers were pleased to tell of their famous relative who lived in the Belvedere as guest of the Medicis. Yet they knew little of Leonardo’s scientific dreams and his lack of recognition in the papal city. Often, Leonardo’s greatest comfort was to return to his notes. The challenge of geometry and the mysteries of the movement of air and water kept him from brooding about his lonely life. Francesco de’ Melzi, Leonardo’s young friend, had more and more taken over the practical responsibilities of his everyday life. Except for his workshop, where the troublesome Georg worked at the making of mirrors, and an occasional small commission for a painting, Leonardo was free to study.