Leonardo DaVinci made contributions to the study of science, medicine and art.  In his relentless pursuit to understand how our world works, he was one of the world's greatest inventors, thinkers, scientists, artists and writers.  A true Renaissance Man, Leonardo DaVinci was a leading voice for reason, logic and science in a world dominated by superstition.

"Flying machines, parachutes, submarines, underwater rebreathing devices, self floatation/ocean rescue devices, swimming fins, pumping mechanisms, water turbines, dredging systems, steam calorimeters, water-well drill, swing bridges, canals, leveling/surveying instruments, cranes, pulley systems, street-lighting systems, convection roasting spit, mechanical saw, treadle-operated lathe, compasses, contact lenses, and military weapons."

DaVinci's genius creates inventions that are far ahead of their time.  In addition to being a world-class inventor, he was a phenomenal painter, his most notable works include, the Mona Lisa, and The Last Supper, as well as The Baptism of Christ.

He also worked to study human anatomy. He dissecting around 30 corpses to get an intimate look at the heart and brain, which he made wax molds of to study further.

Leonardo's studies of heart bought interesting results. At the time it was generally believe that the heart was the source of the 'vital spirit'; it heated the blood which then flowed through the body carrying 'vital spirit'. The idea of the 'noble' heart as just another muscle was never considered and the above ideas, from Aristotle and Greek doctor Galen, were universally accepted. 

His contributions are so vast and cover so many disciplines, or areas of study that it is impossible to include everything in one answer.  

What were Leonardo da Vinci's contributions to art history?

Leonardo da Vinci's greatest contribution to the arts was his emphasis on technical perfection, which entailed extensive research and a great deal of mathematic acumen. He elevated painting to the level of a science, using detailed sketches of the human body and of natural life to study proportion and scale to a degree unprecedented in Western art. This was what he meant when he said that the "eye was the window on the soul," and he was able to use his work to execute paintings with an incredible degree of precision. The Mona Lisa, the Last Supper, and St. John the Baptist speak to the success of this new, almost scientific approach to art.