During these years in Verrochio’s service, Leonardo grew in stature as an artist and rapidly developed into a scientist of promise. He amazed his master when he painted an angel in an altarpiece that had been assigned to Verrochio. He painted it in the new oil colors recently acquired from the Flemish painters. So astounded was Verrochio with its grace that the master vowed he would never lift a brush again if a “mere child” could so surpass him. In this picture there is a tuft of grass beside a kneeling figure, also painted by Leonardo, which indicates by its careful attention to detail the amount of research he did before committing it to canvas. In other paintings he made beautiful drawings of a lily and studies of animals and crabs, giving a hint of what was to come. For, in these preparatory works, Leonardo could not be satisfied until he had thoroughly studied the characteristics of plants and animals in general. Later in life, he was to become more and more absorbed in these researches until they occupied the greater part of his time. In 1469, when Leonardo had been in Florence only two short years, Piero de’ Medici died and was succeeded by his son, the mighty Lorenzo de’ Medici—or Lorenzo the Magnificent, as he was often called. Now the city of Florence felt itself under the control of a man who really knew how to use power. Lorenzo was Florence; nothing happened without his making it happen, and he became one of the most prominent patrons of art and scholarship in all of Italy. If Leonardo was to make any headway in Florence, he would have to make himself noticed by this new Medici ruler. But Leonardo was not yet worrying about how to make himself a success. A young man of seventeen and still an apprentice of Verrochio, Leonardo continued to meet new friends with new ideas. It was at about this time that he met Benedetto Aritmetico, a prominent scholar and mathematician. It is probable that this man drew Leonardo’s attention to the practical needs of industry and commerce so that some of Leonardo’s energy was directed toward the study and improvement of existing machinery and the invention of labor-saving devices. At any rate, during these months Leonardo was walking the streets of Florence, wandering into shops and mills, making careful observations of all the various methods of manufacturing. The more he saw, the more he thought to himself that one man could do the work of many—if only he had the proper machine. He even made drawings of laborers with picks and shovels to see if he could determine by mathematics better ways to swing and hold the tools.