What exactly happened with beer and Leeuwarden in 1487?

Some more info to complement what @PieterGeerkens has found: there's a very scholarly work on the subject on Google Books, Het Bier-oproer te Leeuwarden, in het jaar 1487, in zijne oorzaken en gevolgen by Jacob Dirks; sadly (for me), it's in Dutch and several passages are in Old Dutch or Frisian. But more or less, from what I managed to understand from Google Translate and some common sense, there was a political dispute at the time between the Vetkoopers and the Schieringers (a term that doesn't refer to the community near Leeuwarden but, apparently, to the Cistercian monks' habit, as explained here), which apparently had much to do with both the prohibition and the riots.

While the veracity of this site on the history of crime may be doubtful, it appears to be the only easily located English-language source

The ban was put in place to protect sales of local suds in the city. All beer from outside the city, including that from Friesland’s biggest city, Haarlem, was banned.

But despite this, one innkeeper kept serving Haarlem’s Koyt beer, mostly because he was pressured by bar patrons. Police came to confiscate the beer, and a huge fight started. Customers fled to a sympathetic house, and the homeowner’s brother started getting support throughout several towns. About 8,000 people marched into Leeuwarden the next day, demanding Haarlem beer and fair trade. They were ignored, and promptly sacked the city.

The ban was eventually lifted.

When we think of foreign beer today anyone not from Canada (and it's bizarre panoply of inter-provincial alcohol regulations and taxes) usually thinks of imports from other countries, or even other continents. However the people of Leeuwarden simply wanted the freedom to purchase beer brewed a few days horse ride (150 km on todays map) away, their national capital of Haarlem. It would appear that the local brewmaster(s) of Leeuwarden was unable to compete on quality and or price, and instead sought a legal monopoly. His potential customers didn't have the same zeal for local brew.

Numerous craft breweries around the world now celebrate this day, as an excuse for patrons to enjoy locally-brewed craft beer; which seems as good a reason as many, to me, to enjoy a local pint.

As an exercise for my studies of Dutch, I will continue to look for any Dutch sources that might be able to substantiate the claimed details.

Update - from Het StadtFries by K. Fokkema, published 1937, page 9:

De verwarring werd groter in Friesland, hoewel men poogde door gaerlegers en verbonden de volkomen ontbinding tegen to gaan . Leeuwarden is er vooral op uit de „delen" bijeen to houden het trachtte in hat klein dezelfde rol to spelen als Groningen : vooral de belemmeringen die de koopman ondervond in de omliggende gebieden, moesten worden tegengegaan.

Het was echter niet stark genoeg om zich to handhaven : in 1487 ward hat tengevolge van hat bier-oproer, uitgebroken doordat buitenlieden in de stad verboden haarlemmer bier dronken, door de Schieringers ingenomen en gedeeltelijk verwoest .

which my very rudimentary Dutch, assisted by Bing, translates as

The confusion became larger in Friesland, although one aimed against dissolution by gaerlegers and connected the perfectly to go. Leeuwarden is, above all, from the "share" it tried to keep together in the same role to play as small hat Groningen: especially the barriers that the merchant encountered in the surrounding areas, had to be countered.

It [Leeuwarden] was, however, not strong enough to maintain itself; in 1487 as a consequence of the Beer riots, caused by non-residents of the city who were banned from drinking Haarlem beer, it was taken by the [people of] Schieringen and partially destroyed.

However, I have clearly missed something in translation as Schieringen is (today) a community center only about 1 km from downtown Leeuwarden.

Update

Ha! No wonder Bing struggles so with a translation - the original is in the Friese dialect of Leeuwarden rather than even in historical Dutch. The full title is:

The City Friese - A contribution the history and grammar of the dialect of Leeuwarden.

I came across this question today, and saw that JMVanPelt in his answer mentioned a Dutch book for which no English translation was available. I have translated the relevant parts of it below. I have tried to stay as close as possible to the original phrasing. Below, all emphasis is as in the original, comments between round brackets are also in the original, and comments between square brakets are mine. It should be said that I am by no means an expert on history or historic use of the Dutch language, so the translation below might contain a few translation errors caused by a change in the meaning of words or phrases since 1867. Also, I'm not native in English, so I apologize in advance for any lingistic errors.

The beer-revolt at Leeuwarden in the year 1487, in his causes and consequences -- a reading of Mr. J. Dirks

In our research-loving time, in which people, rightfully so, start to show less interest in the story of wars and more in the story of the development of social situations, would it be a not unpleasant and also useful task to find out how many a war and skirmish has been borne out of a sometimes very simple state-householding [staat-huishoudkundigen] mistake. I repeat it, out of a state-householding, economic-political and not just political mistake.

This image floated before my mind, when I once read, what earlier and later authors have written about the well-known Beer revolt at Leeuwarden, which happened in the year 1487; an event, that had the occupation of that city on St. Jacobi's day (25 July) of that year, the murder of the sensible alderman Pieter Sybrands Auckama, nicknamed Pinkert, the death and the abduction of many other citizens and the sack of the city as its sad consequences.

There is still a, even today by far not yet everywhere for the rising light of science vanished foolishness, that nothing advances the prosperity of a nation more, than the protection of domestic production, by prohibition of the import from outside, or by very high taxing of objects of foreign origin, especially of those, which are also created domestically.

There are two goals people think to achieve with such a course of actions [handelswijze], the first: the advancement and development of the own domestic production, and the other: keeping the money inside the nation's own borders.

Also in our fatherland this thought used to rule, and only the last tax reforms, which came to be since 1848, have been able to lift the prohibitions and restrict the incoming rights [?] to purely fical ones. The character of protecting rights has been taken from them, but not without a fight.

The further we climb up in the history of the Netherlands, the more traces of protection we discover, first at the independent seven provinces, and even earlier at the independent parts and cities of those. Leeuwarden gives of this in the year 1487 a remarkable example.

[ After this introduction, Dirks gives some background of the event. In the last quarter of the fifteenth century, Friesland was in a conflict between two fractions, known as the Vetkopers and the Schieringers. The city of Leeuwarden was usually at the side of the Vetkopers. On 20 April 1482, the cities of Leeuwarden (Vetkopers), Bolsward (Vetkopers), Sneek (Schieringers) and Sloten (Schieringens) signed a treaty for a period of four years, in which the citizens and inhabitants of these cities where allows to buy, sell and travel between each other, "fry ende feylich" (freely and savely). However, after this treaty expired in 1486, new prohibitions where created in Leeuwarden, amongst which the rule that beer from Haarlem (known as Kuitbier) was not to be sold, but only beers brewed in Leeuwarden. Dirk notes that this rule was at that time of much more importance than such a prohibition would be in our "coffee, tea and jenever-drinking time". In 1487, and even long after that, beer was the popular drink, and was brewed and imported in very large quantities. As such, beer brewing was the livelyhood of many people, and the brewers guild in Leeuwarden was politically very powerful. On the other hand, the beers from Haarlem where of higher quality, because the dunes in that region make the water used for brewing more pure. So this prohibition was controversial at least.]

On a certain day, possibly a market day, in the month July 1487, a few farmers in Leeuwarden where drinking kuit [the Haarlem beer] in the house of a beertapper, who still had a keg left over or stored, and who could or would not resist the demand to pour a good glass of beer and make some extra money. The Schieringer farmers did not care about the prohibition of the Vetkopers. -- This atrocious fact comes immidiately to the ears of the brewers; they storm into the house, which was probably located in the Hoekster-end, find the transgressors of the ordinance, and forbid them to drink Haarlem kuit. The farmers, who had been drinking the good, strong beer (because forbidden fruit tastes sweet) for a long time already, are not in the mood to obey. People start to altercate and to fight. As time progresses, more citizens are coming towards the clamor, forcing themselves into the house, helping the brewers and making the farmers lose the fight [doen de boeren het onderspit delven]. They [the farmers] walked out of the beer house, "and fled to Pieter Cammingha huys in Leeuwarden", today known as the Amelandshuis, situated close the the Gardens (the location, where on the 25 July 1487 the city was attacked from the east). The citinzenry of Leeuwarden resented the Haarlem beer drinking farmers so much, "that they came with their guns to the stins, and wanted the transgressors of their prohibition in their hands." Pieter Cammingha however, was not a man to obey this command at once. He was a Schieringer, "much loved, over all of Friesland, by the Schieringer lords." He had become Lord of Ameland a year before because of the death of his father Haye (married in 1458 with Doedt Dekema), and the youthfull [Dirks remarks in a note that Pieter Cammingha cannot have been older than 28 here] rich nobleman, borne from a family that once held seven stinses and houses in and around Leeuwarden, did not give in to the demands of those, who surrounded his house. He was unwilling to give a couple of defenseless farmers, who by chance had fled to him, to the fury of a mob that was made even more angry by a false rumour.

[ Dirks explains that there was a rumour that Pieter Cammingha had been fortrifying his estate and loading it with provisions and ammunitions, and that this young Schieringer lord was preparing to attack the mostly Vetkoper city of Leeuwarden from within, as soon as other Schieringer forces would attack the city from outside. However, a group of Jacobian monks from a nearby monastry, amongst which a monk known as Brother Hendrik, came to the site and were let inside to house, and later testimony of Brother Hendrik shows that the Cammingha house was most certainly not prepared for siege.

Pieter Cammingha asks Brother Hendrik after his mother Doede, who stayed at the monastry, and he sends the brother to ask for this mothers advice. His mother adviced Pieter not to fight, but to make a deal with the mob. ]

When brother Hendrik had communicated this message of the sensible and, as we will see later, valiant woman, Pieter Cammingha spoke "to the citizens and community, which were around the house: Ye good citizens! These man, who fled to my house, them I can hardly just throw out, now that they have fled to me and desire to have my protection." No, he did not want to surrender those poor refugees now, but as Schepen [head of the police?] of Leeuwarden he promised, that justice will be done. Even though there only was a transgression of a beer ordinance, of which he disapproved, there had been a fight, and the case would the next day be brought before "the common council of Leeuwarden". Against this he would not resist. -- After this a truce and then a pact was made, under the condition, that Pieter Cammingha would stay quiet, when the enemies came for the city, like the rumour said. Doedt [Pieter's mother], says brother Hendrik, sent after this her own ring by Lord Lolle, of blessed memory, to Wytze, (her son-in-law Wytze Dekema married to Sjouk Cammingha), and let him know, that everything in the city was smoothed out again and that the people would leave. The sensible woman might have feared, that Wytze would march from Oenema-state, close to Wirdum, where he probably lived, to Leeuwarden to relieve his brother-in-law.

But although to quiet in Leeuwarden now had more or less returned, outside a heavy tempest broke loose. Everywhere in Oostergoo and Westergoo, where the Schieringers had power, were the bells ringing to call them to arms; with the consequence, that they on 24 July 1487, the evening before St. Jacob, together with the cities of Sneek and Franeker, had brought together at the Barrahuis, one hour south of Leeuwarden, a force, which they say has no less than 8000 man. With this they meant to attack and humiliate Leeuwarden.

But before they tried to execute this intention, something happened, that reminds us of many an event in the Roman history, the appearance of women as peacemakers.

In the morning of the 25 July left "two honest widows, Vrouck (Auckama), late Kempo Vnya's wife, and Doedt, late Haye Heringa's wife", says Worp [a history book mentioned before in the text], the city and came to the army at Barrahuis. The latter was the same already mentioned Doedt Dekema, the mother of Pieter Cammingha [...]. They approached the lordships and citizens, "desiring and preying, that they would march away from Leeuwarden, to prevent all evil and bloodloss. Had the Leeuwarden citizens done them any wrongs, then from both sides good and wise men would be named, who would settle the conflict and the argument." Thus goes the simple story in the naive Worp [the history book]. Gabbema [Frysian writer], the style destroyer [stijbederver] of Gybert Japiks [Frysian poet], the lame imitator of Hooft and Tacitus, found this opportunity to beautiful not to include a speech in grandiose style of several pages, which the honorable matrons Vrouck and Doedt have probably never held. -- The lordships and citizens set up a council, talk about the proposal, and let Jouke, pastor of the nearby Goutum, write a letter to the city of Leeuwarden, that truly, considering the exited state in which the offended party must been, commends the sensibility of the leaders of the Schieringers.

They proposed simply the restoration of the in April 1486 expired treaty of April 1482: each would be able to freely buy and sell, where-ever it pleases them; each would amongst the others "peacefully walk and exist;" each would in his honor, state and liberties stay as before. Several other "articles," seemingly of less importance, possibly in the spirit of the treaty of 1482, for enforcement of the main clauses, were added.

They sent the women back to Leeuwarden with this letter, with this condition: if the letter was sealed, as a sign of agreement, and returned to the army in the afternoon, -- everyone would return home and leave the city at peace; but neglected they to do so and was the letter not sealed and returned on time, then the city would be attacked with force.

As soon as the letter in Leeuwarden was read to all the citizens, Pieter Sibrantszoon (Auckama), alderman of the city (a wise, [verfaeren?] man, says Worp), with some other calm citizens, in consideration of the imminent danger, gave the governance the advice to seal the letter and send it back. Leeuwarden was by the clauses of this letter in no way harmed. But this sensible calm advice was, like so many others, by unwisdom spurned, by temper not understood, and fell, by self-interest drowned, on deaf ears. "The whole group of citizens and inhabitants of Leeuwarden," says Worp, "shouted that they would immidiately hit those who would seal the letter to death, for they did not want to allow that those from the Westergoe would buy or sell from those in Oostergoe." Even the Japanese have not be able to hold on to such a system of occlusion and indeed it would end very badly very soon for the self-interested Leeuwarders. Their action was even more unwise, because, aside from the fact that the city was not completely on all sides protected, a few days before a large number of armed men from the city was dispatched to Bolsward, with whom a separate treaty was made, to help Ige Galama of Noordwolde.

The Schieringers did not hesitate now, when they heard that the Leeuwarders would not seal their letter, to march from Barrahuis "in furious rage" and with all of their force. They attacked the city in force at the same day "just before vespers", says Worp, "at three o'clock", says Gabbema, at the east side near the Gardens. There the city was at that time still open, after people started in 1481 to surround it with a new ditch and a high wall. Nevertheless the Leeuwarders defended bravely, "devoutly", against the first attack, and the Schieringers left four deaths on that location. But they were not detered by this; they repeated the attack and in fact so powerfully, that, after some of the citizens had been killed, the others fled the so bravely manned defenses and the Schieringers conquered the city.

"They killed first Mr. Pieter Sibrantszoon, Pinckert, Bachelor in both laws, after he had confessed." So in cold blood almost was this brave compatriot, who deserved a very different fate, even from the sides of the Schieringers, murdered. Long after these events, this atrocity stayed in the memory of the Leeuwarders.

[ Dirks goes into some details about where and under what circumstances Auckama would have been killed, and which evidence remains. ]

The richest citizens were captured and locked away in Sneek or in stinsen on the countryside; the whole city was looted and robbed. Of the two large cans [? bussen] in Leeuwarden was the biggest, perhaps to heavy to be readily transported, broken to pieces, and the other was taken away.

Worp Lieuweszoon (Juckema) of Boxum was granted the control of the city by the Schieringers. "And Leeuwarden," says Worp, "was after this for some time in much suffering and grief."

Many citizens, who had fled to the defenses at the non-attacked side, went to Ige Galama of Noordwolde, "for Yge was a [doordryuende], brave man, full of war, and the leader of all the Vetkopers in Westergoe, and had always been good to Leeuwarders." Strenthened by his power and the earlier mentioned troops, over which Juw Jongema of Bolsward had the command, a guerilla war of pillage and looting started against the Sneekers, the sworn enemies of the Leeuwarders: because, says Worp, "the Sneekers were always good folks, and in line with the Schieringer party, and the Leeuwarders have always been bad folks," (i.e. they did not see eye to eye with the Scheringer-minded lordships like Piter Cammingha) "and were in line with the Vetkoper party." -- The story of this further war however is outside of the scope of our communication.