Popular revolts in late medieval Europe were uprisings and rebellions by (typically) peasants in the countryside, or the bourgeois in towns, against nobles, abbots and kings during the upheavals of the 14th through early 16th centuries, part of a larger "Crisis of the Late Middle Ages". Although sometimes known as Peasant Revolts, the phenomenon of popular uprisings was of broad scope and not just restricted to peasants.

Background
There were five main reasons for these mass uprisings including 1) an increasing gap between the wealthy and poor, 2) declining incomes of the wealthy, 3) rising inflation and taxation, 4) the external crises of famine, plague and war, and 5) religious backlashes.

Causes
The first reason was because the social gap between rich and poor had become more extreme. The origins of this change can be traced to the 12th century and the rise of the concept of "nobility". How one dressed, behaved, manners, courtesy, how one spoke, what one ate, education, all became a part of the noble class making them distinct from others. By the 14th century the nobles had indeed become very different in their behavior, appearance and values from those "beneath".
In urban centers, the early capitalist enterprises connected with long-distance trade and the textile industry had given rise to an urban underclass who were prone to riot in times when the price of bread was high. The perpetual apprentices who could not purchase a mastership in the tightly-controlled guilds were quick to express their resentment, and in university cities, students might be enlisted.

Rich and poor
The second reason was a crisis for the nobles with declining income. By 1285 inflation had become rampant (in part due to population pressures) and nobles charged rent based on customary fixed rates, based on the Feudal system, so as the price of goods and services rose (from inflation), the income of nobles remained stagnant (effectively dropping). To make matters worse, the nobles had become accustomed to a more luxurious lifestyle that required more money. To address this nobles illegally raised rents, cheated, stole, and sometimes resorted to outright violence to take what they wanted.

Inflation
Thirdly, kings needed money to finance wars and resorted to devaluing currency, by cutting silver and gold coins with less precious metal, which resulted in increased inflation and in the end, increased taxations.

Taxation
Fourth, the 14th century crisis of famine, plague and war put additional pressures on those on the bottom. The plague drastically reduced the numbers of people who were workers and producing the wealth.

External crisis
Finally, layered on top of this was a popular ideological view of the time that property, wealth and inequality was against the teachings of God, as expressed through the teachings of the Franciscans. The sentiment of the time was probably best expressed by preacher John Ball during the English Peasant Revolt when he said "When Adam delved and Eve span, who was then the gentleman?". In other words, "gentleman" are nobles, all men are equal before God. It was a cry for a leveling of society where no man is above any other.

Religion

The Peasant revolt in Flanders 1323-1328. Beginning as a series of scattered rural riots in late 1323, peasant insurrection escalated into a full-scale rebellion that dominated public affairs in Flanders for nearly five years.
The St. George's Night Uprising of 1343-1345 in Estonia.
The Jacquerie was a peasant revolt that took place in northern France in 1356-1358, during the Hundred Years' War.
The English peasants' revolt of 1381 or Great Rising of 1381 is a major event in the history of England. It is the best documented and best known of all the revolts of this period.
The Budai Nagy Antal Revolt broke out in Transylvania in 1437. The military tactics of the rebels were inspired by the Hussites wars (for example, the use of battle wagons).
The Kent rebellion of 1450 led by Jack Cade.
The Rebellion of the Remences in Catalonia in 1462 and 1485.
The Cornish Rebellion of 1497 in Cornwall and London.
The 1514 peasant's war led by György Dózsa in the Kingdom of Hungary.
The Slovenian peasant revolt of 1515 was a peasant revolt which engulfed most of what is now Slovenia.
The Knight's Revolt of 1522-1523 in Germany.
The Peasants' War of 1524-1526 in the Holy Roman Empire.
The Pilgrimage of Grace in 1536 in England.
The Dacke Feud of 1542 in Sweden.
The Wyatt's rebellion of 1554 in England.
The Prayer Book Rebellion of 1549 in Cornwall and Devon.
The Croatian and Slovenian peasant revolt of 1573 was a large peasant revolt in Croatia.
The Club War uprising 1596 in Finland.
The peasant wars of Ivan Bolotnikov and Stenka Razin in the 17th-century Russia.
The Swiss peasant war of 1653. Notable rural revolts

The Zealots, Thessalonica, Byzantine Empire, 1342-1350.
The revolt of Cola di Rienzi in 1354.
The Revolt of the Ciompi in 1378. Peasant