Around the year 1000, growth resumed in Europe. This was the product of the work of peasants, who were even more exploited and despised, especially by city dwellers who were making a comeback. The rise of commercial agriculture was based on cereals, the main source of profit for the ruling classes. The banks of the River Po and the coasts of the North Sea were drained to conquer new wheat lands. The destruction of these wetlands disrupted the peasant economy and led to catastrophic flooding, the effects of which are still felt today. In the 14th century, famine, war and plague put an end to growth. The era of the great anti-feudal revolts began, with their mystical and egalitarian overtones. From the French Jacquerie of 1358 to the German Peasants' War of 1525, all were drowned in blood.