The 14th century in England saw the Great Famine and the Black Death, catastrophic events that killed around half of England's population, throwing the economy into chaos, and undermining the old political order. Social unrest followed, resulting in the Peasants' Revolt of 1381, while the changes in the economy resulted in the emergence of a new class of gentry, and the nobility began to exercise power through a system termed bastard feudalism. Nearly 1,500 villages were deserted by their inhabitants and many men and women sought new opportunities in the towns and cities. New technologies were introduced, and England produced some of the great medieval philosophers and natural scientists. English kings in the 14th and 15th centuries laid claim to the French throne, resulting in the Hundred Years' War. At times England enjoyed huge military success, with the economy buoyed by profits from the international wool and cloth trade, but by 1450 the country was in crisis, facing military failure in France and an ongoing recession. More social unrest broke out, followed by the Wars of the Roses, fought between rival factions of the English nobility. Henry VII's victory in 1485 conventionally marks the end of the Middle Ages in England and the start of the Early Modern period.