Benito Mussolini was an Italian politician and leader of the National Fascist Party, known for establishing a totalitarian regime in Italy during the early 20th century. His rise to power in the aftermath of World War I was characterized by economic turmoil, social unrest, and a desire for national rejuvenation, which he promised to deliver through his fascist ideology. Mussolini's aggressive policies and militarism played a significant role in the lead-up to World War II as he sought to expand Italy's territory and influence.