After the fall of Rome, Italy fell into a dark sleep, and wasn't reawakened until the 11th century. Autonomous city-states emerged and these tiny republics began to revitalize their cities and build on a massive level not witnessed since the rise of Rome. In the late 15th and 16th centuries, alliances among various city-states continually shifted as foreign superpowers tried to sink their claws into Italy. The masters who are best known for creating the works of art and architecture of the Renaissance, were also the greatest military and civil engineers of the time.