Polymathy is the state of having deep knowledge or expertise across a wide range of subjects. True polymathy involves deep mastery in multiple fields, not just wide-ranging but superficial knowledge.
A classic example of polymathy is Leonardo da Vinci, who lived from 1452 to 1519, during the Italian Renaissance. Da Vinci painted famous works, including the Mona Lisa and The Last Supper. But he wasn't just a painter; he was also a scientist, engineer, inventor, anatomist, writer, and musician. While most people specialize in one specific field, a polymath excels in many areas. In modern times, think of of a world-class neurosurgeon who also writes award-winning poetry and designs high-tech software.