The Renaissance began as a rebirth of ideas and values from antiquity following the decline of the Roman Empire and the cultural stagnation of the Middle Ages. During this period, the Black Death pandemic killed 30-60% of Europe's population, weakening social institutions. Meanwhile, the fall of Constantinople brought Greek texts to Italy, sparking renewed interest in classical philosophy. Early Italian Renaissance artists like Giotto and Duccio began moving away from the flat, abstract styles of medieval art towards greater naturalism by incorporating perspective, anatomy and other techniques from antiquity.