This installment of PBS's educational "Empires" series focuses on the Medici, one of European history's most influential merchant families and patrons to some of the greatest artists in the Italian Renaissance -- including Leonard da Vinci, Michelangelo and Raphael. Movers and shakers from the 14th century onward, the Medici used any means necessary, whether it be money or merciless tactics, to leave a lasting impression on art and science.