The document summarizes the major crises and revolutions that occurred in Europe during the 14th century. Specifically, it discusses (1) the factors that led to famine and plague across Europe, including overpopulation, stagnating agriculture, and changing climate; (2) the devastating impact of the Black Death pandemic from 1347 to 1350, which killed around 1/3 of Europe's population; and (3) the resulting social upheaval, including peasant revolts and the 1383 revolution in Portugal that led to a new ruling dynasty.