The best example of a 'patronal revolution'
In the Middle Ages the theory of revolutions was not developped yet to the level known in Renaissance and later on. The most popular type of medieval revolution was a 'patron' one, i.e. replacement of one feudal lord by another. Sometimes the difference between feudal lords was big enough to give such a change a revolutionary meaning.
The most interesting (IMHO) cases of 'patronal revolution' was the Swiss one. In XII century the Habsburg dynasty beame the most important feudal family in the area of what we call today Switzerland. Their groving apetite for power and wealth encountered resistance of free peasants and shepherds in highland and forested communities (cantons). In the rest of Europe of those days such a resistance was eventually crushed and replaced by ruthless slavery. Swiss peasants could take advantage of terrain and - let's admit it - their own political cleverity.
The Habsburg had a formidable opponent: the Holy Roman Empire. It was constituted largely by the Germans, but it had nevertheless vital interests in Italy. Therefore, securing a reliable passage from Germany to Italy for the Empire was a question of utmost priority. For obvious reasons, the emperor disliked the idea of a powerful feudal resistance seizing this strategical passage, and he was anxious to support the peasant resistance.
In 1231 the first Swiss canton - Uri - obtained the imperial order releasing it from all local feudal obligations. They were substituted by direct servitude to the emperor. It was therefore rendered a free peasant republic, subjected only to the remote and not interfering emperor. Soon another mountain and forest cantons got similar orders (Freiheitsbriefe). The Habsburgs won nevertheless support of the 'city' cantons, what led to numerous local skirmishes.
On August 1st, 1291 the three forest cantons signed a pact of mutual cooperation against the Habsburgs. This day is regarded now as the beginning of the Swiss Confederation, and it's anniversary is now a Swiss national holiday. The pact was recognized by the Empire and contested by the Habsburgs. The actual war begun in 1314, when the free cantons seized a monaster in Einsiedeln, being de facto a Habsburg remote outpust.
The Habsburgs responded in 1315, when prince Leopold entered Switzetrland with a column of some dozen thousand knights and mercenaries. This powerful army was enough to conquer a medium European state of its age. Prince Leopold had no doubts about his own victory (he took lots of rope to tie his prisoners)!
Well, you should never underestimate those, who has little to loose and everything to gain :). On November 15, 1315 prince Leopold's army was crossing a tight passage between the lake Aegeri and the high mountain. Suddenly, near the Morgarten village, a landslide of heavy rocks and tree logs started to fall on prince's troops, pushing them towards the lake. It was the higlanders, who were hidden high in the mountains and threw all this crude weaponry down to their enemies.
The heavily armored knights had no possibility to strike back. They could not climb the steep and rocky mountains, they could not even control their own panicked horses. The rocks and logs decimated them. Then the peasants charged the disrupted army of the prince. They were armed only with axes and pikes, but it's a powerful weapon in a crowd. Those knights who were not killed by rocks or did not drown in the lake (ever tried to swim in 50-kg plate armour?), were mercilessly slaughtered like pigs. Ay caramela!
Prince Leopold and few survivors escaped in panic to their castle in Winterthur. The Habsburgs now had no military power, but the peasant federation still had to combat pro-Habsburg city cantons. They achieved victory by a combination of diplomacy and slaughter (a very good way to achieve a victory!). In 1332 the city of Luzern joined the federation, soon accompanied by Zurich (1351) and Bern (1352). A bit of slaughter was necessary here and there, especially in Zurich (I never liked this city, anyway).
In the years of 1386-1388 Habsburg armies tried to conquer the revolted cantons, but again, to no avail. Peasant axes and bows proved to be excellent weapon in dense forest and high mountains. Aftre more blody defeats in 1393 the Habsburgs signed peace treaty with the federation, now consisted of 8 cantons.
The federation never developped a single, centralist state government (not even until today, one could say!). The cantons retained their own political forms of government, some being oligarchic republics, some being peasant communes governed by some kind of direct democracy. Sometimes, when a state-level decisions was necessary, delegates of all cantons met on special meeting, later called a Federal Assemby, but no state-level executive power appeared until XVII century.
And what about Wilhelm Tell, his crossbow and an apple on the head of his son? Well, it's just an apocryphical tale, located in XIII-century canton of Uri, but written probably in XV century. Please note, that this is one of the most commonly recognizable revolutionary hero in European culture!
As you can see, in the Middle Ages replacing feudal lord from the local one (the Habsburgs) by a remote one (the emperor) could lead to powerful revolutionary results. The Swiss case is probably the fullest realisation of what could be achieved by means of 'patronal revolution'. The peasant republic developped during this revolution, and it eventually turned out to the richest countries of Europe. Frankly, this is my biggest personal dream: to become a Disgustingly Rich Person some day in my live and be a happy rentier living somewhere near Vevey in a palace over the lake...