Niccolò Machiavelli
Niccolò Machiavelli (3 May 1469-21 June 1527) was an Italian historian, politician, diplomat, philosopher, and writer based in Florence during the Renaissance. He was for many years an official in the Florentine Republic, with responsibilities in diplomatic and military affairs. He was a founder of modern political science, and more specifically political ethics. He also wrote comedies, carnival songs, and poetry. His personal correspondence is renowned in the Italian language. He wrote his masterpiece, The Prince, after the Medici had recovered power and he no longer held a position of responsibility in Florence.
"Machiavellianism" is a widely used negative term to characterize unscrupulous politicians of the sort Machiavelli described in The Prince. The book itself gained enormous notoriety and wide readership because the author seemed to be endorsing behavior often deemed as evil and immoral.