Marcus Auerilius

The illegitimate son of a 25-year-old notary, Ser Piero, and a peasant girl, Caterina, Leonardo was born on April 15, 1452, in Vinci, Italy, just outside Florence. His father took custody of the little fellow shortly after his birth, while his mother married someone else and moved to a neighboring town. They kept on having kids, although not with each other, and they eventually supplied him with a total of 17 half sisters and brothers..

Growing up in his father's Vinci home, Leonardo had access to scholarly texts owned by family and friends. He was also exposed to Vinci's longstanding painting tradition, and when he was about 15 his father apprenticed him to the renowned workshop of Andrea del Verrochio in Florence. Even as an apprentice, Leonardo demonstrated his colossal talent. Indeed, his genius seems to have seeped into a number of pieces produced by the Verrocchio's workshop from the period 1470 to 1475. For example, one of Leonardo's first big breaks was to paint an angel in Verrochio's "Baptism of Christ," and Leonardo was so much better than his master's that Verrochio allegedly resolved never to paint again. Leonardo stayed in the Verrocchio workshop until 1477 when he set up a shingle for himself.

In search of new challenges and the big bucks, he entered the service of the Duke of Milan in 1482, abandoning his first commission in Florence, "The Adoration of the Magi". He spent 17 years in Milan, leaving only after Duke Ludovico Sforza's fall from power in 1499. It was during these years that Leonardo hit his stride, reaching new heights of scientific and artistic achievement.

The Duke kept Leonardo busy painting and sculpting and designing elaborate court festivals, but he also put Leonardo to work designing weapons, buildings and machinery. From 1485 to 1490, Leonardo produced a studies on loads of subjects, including nature, flying machines, geometry, mechanics, municipal construction, canals and architecture (designing everything from churches to fortresses). His studies from this period contain designs for advanced weapons, including a tank and other war vehicles, various combat devices, and submarines. Also during this period, Leonardo produced his first anatomical studies. His Milan workshop was a veritable hive of activity, buzzing with apprentices and students.

Alas, Leonardo's interests were so broad, and he was so often compelled by new subjects, that he usually failed to finish what he started. This lack of "stick-to-it-ness" resulted in his completing only about six works in these 17 years, including "The Last Supper" and "The Virgin on the Rocks," and he left dozens of paintings and projects unfinished or unrealized (see "Big Horse" in sidebar). He spent most of his time studying science, either by going out into nature and observing things or by locking himself away in his workshop cutting up bodies or pondering universal truths.

Between 1490 and 1495 he developed his habit of recording his studies in meticulously illustrated notebooks. His work covered four main themes: painting, architecture, the elements of mechanics, and human anatomy. These studies and sketches were collected into various codices and manuscripts, which are now hungrily collected by museums and individuals (Bill Gates recently plunked down