1452: Born in Florence, Italy, Leonardo da Vinci was arguably the leading artist of the Renaissance. Some of his best-known paintings include The Last Supper and La Gioconda, also known as the Mona Lisa. Although most people think of Leonardo as an artist, he actually spent more time on scientific projects than on painting. Leonardo documented many of his ideas and studies along with copious drawings in many notebooks, projects that occupied him throughout his life. The notebooks deal with four major themes--the science of painting, architecture, the elements of mechanics, and a general work on human anatomy. Later he added notes on his studies of botany, geology, flight, and hydrology. Leonoardo's studies demonstrated a scientific and mechanical inventiveness that was ahead of his time.
While in the service of the Duke of Milan, Leonardo worked not only as a painter and sculptor but also as a designer of weapons, buildings, and machinery. For example, he created designs for a tank and for submarines. It was at this time, too, that he made his first anatomical studies. He kept his sketches, designs, and ideas in a series of codices and manuscripts. One of these, the Codex Leicester, was recently purchased by Bill Gates for $30 million.