Medieval cities often had fraught relations with their regional clergy. Many towns at some point called their local bishopric overlord according to Feudal law. But eventually, some forced the episcopal ruler out of town and established their autonomy by acquiring the charter of a free city or free imperial / royal city.
The prelates of the Church, many of whom were from families of the warrior aristocracy, did not take this lying down, and there were many ongoing disputes between burgher and bishop lasting multiple generations. Sometimes these broke out into pitched battles, such as when the town of Strasbourg defeated their prince-archbishop Walter von Geroldseck in an open field battle at Hausbergen in 1262, capturing 86 of his knights and killing 1370 of his men; or when the Archbishop of Mainz Adolf II von Nassau sacked and recaptured that city in 1462, executing 400 people, exiling many more (including Johannes Gutenberg) and ending the autonomy of that town.
More often these conflicts consisted of endless lawsuits, diplomatic wrangling, occasional raids and kidnappings, and small skirmishes. The prince-bishops also used their unique episcopal powers such as the ability to place individuals or entire communities under interdict or even excommunication. In extreme cases, they might also attempt to invoke the inquisition.
Partly because these rivalries went on for so long, it’s difficult to find comprehensive let alone unbiased histories of the ongoing feuds between town and bishop. But one good if not perfect source is the magisterial history of the cleric, and eventually bishop Jan Długosz of Poland. His ‘annales’ which cover the history of Poland from 965 to his own death in 1480, are not free of bias but are quite thorough, well written, and by the standards of the day, fairly even handed.
From these annals, we find here an interesting example of strife between the citizens of Wrocław (aka Breslau to it’s German-speaking inhabitants, and Vratislav to its Czech overlords) vs their local Bishopric. This lasted from 1337 through 1341, during the reign of bishops, Nankier Kołda (aka Nanker).
The following excerpts from the annals of Jan Długosz cover the key incidents of the conflict:
Wroclaw helps King John of Bohemia ransack the bishop’s cathedral and castle, with the help of wine – From the entry for 1337
The King of Bohemia [King John the Blind], having by intrigue, flattery or promises subjugated the Polish dukedoms in Silesia and illegally occupied the town and duchy of Wroclaw… now plunders the cathedral at Wroclow, which the Silesian dukes endowed. He orders the Bishop and Chapter to surrender its castle at Milicz, and, when Bishop Nanker, a courageous main, disdainfully refuses to obey, the King brings up a powerful force, reinforced by some citizens of Wroclaw, and attacks the castle which was held in the name of the Wroclaw chapter by Henry of Wierzbno the archdeacon. Seeing that it will not be easy to capture it, for the castle has good defenses, and learning that the Archdeacon is an inveterate wine-bibber, he sends him some friendly Silesian knights with bottles of wine in profusion, as a result of which they are eventually able with threats and promises to induce the Archdeacon to evacuate the castle with his entourage.
The Bishop sends letters and messengers to the King, demanding the return of the castle, and when this is refused, imposes an interdict on the whole diocese. Further attempts to obtain the return of the castle are made later, when the King comes to Wroclaw. When these, too, are unsuccessful, the Bishop, ordering all his clergy to accompany him, goes to the King …they find the King in a small room adjacent to the refectory. They knock loudly on the door, and, when the King tells them he is occupied with other matters and cannot give them audience… the Bishop takes hold of his crucifix and says: “By the authority of Almighty God I excommunicate you as a plunderer of Church goods and pronounce you excommunicated in the name of the Father and of the Son and the Holy Ghost.”…
The Bishop leaves Wroclaw and orders all churches in Wroclaw to be closed. Nonetheless the doors of the three parish churches of St. Mary Magdelen, St. Elizabeth and the Holy Ghost are forcibly opened and services are resumed on the orders of the King and the city-fathers. Pope Benedit XII, who is in Avignon, praises the Bishop for what he has done and orders him to persist. He also confirms and increases the penalties imposed on the King and the citizens of Wroclaw, on whom he pronounces anathema.”
Wroclaw sees off the inquisitor – From the entry for 1339
“Bishop Nanker of Wroclaw realizes that sterner measures will be required, if the obstinate rebellion of the citizens and city fathers of Wroclaw is to be quelled, since those taken by their own bishop, and indeed, by the Holy See, have achieved nothing in more than a year; indeed, the situation is getting steadily worse and doing considerable harm to the Church. So, the Bishop summons the Inquisitor of Heretical Faults in the diocese, Brother John of Schwenkenfeld of the Dominicans, a man of blameless and exemplary life, and explains to him the obduracy of the citizens of Wroclaw and requires him to take action against them for disregarding the punishments laid on them Church, thus making themselves suspect of heresy [In therefore, in theory, legally liable to investigation by the inquisitor]
Brother Jan is well acquainted with the misdemeanours of the citizens of Wroclaw and promises to try and exert his authority. He goes to Wroclaw and, one Sunday, from a pulpit set up before the City Hall, speaks to a huge throng, rebukes them for abusing holy places and for their obstinacy and begs them to return to the bosom of the Church. He concludes by challenging them to appear before him the next day and answer the accusations laid against them. When the citizens concerned fail to appear, the Inquisitor, inspired by the Holy Spirit, goes in person to the City Hall and calls upon the city fathers he finds gathered there to delay no longer in returning to the bosom of the Church, for otherwise they will call down upon themselves the wrath of God.
He tells them, too, that he is determined to use all the means his office allows to quell their intransigence [in theory this would include excommunication, torture, execution etc.]. After a long discussion, the Inquisitor concludes that he is getting nowhere and leaves the City Hall pursued by curses, insults and grinding of teeth; indeed, he is lucky not to have been assaulted.”
The old Bishop dies, Wroclaw pays assassins 30 marks to kill the Inquisitor – from the entry for 1341
Bishop Nanker of Wroclaw dies on April 10, apparently suddenly, but it is also said that he was ssecretly killed on the orders of the King of Bohemia [King John, Luxeumburg family, father of Emperor Charles IV, died at Crecy] in retaliation for his public excommunication of the king. The city fathers of Wroclaw are delighted by the death of their bishop and regard this as a victory over the Church. They now go to King John and register against the Wroclaw inquisitor, alleging that he has insulted and condemned them. …
“While spending the night at the Dominican monastery of St. Clement, two thugs come to the Inquisitor’s cell and knock on the door, demanding to be given confession. The Inquisitor is preparing a sermon and tries to put them off, but they tell him that, if he does not listen to them while they still have a spark of contrition left, it will be too late. At this, the Inquisitor emerges, receives three thrusts from their two swords and drops down dead. The King suspects the starosta of having planned the murder with the city council and arrests them, but when they on oath deny their guilt they are released. A year and a half later the two thugs are arrested on another charge and condemned to death. They then confess to the previous crime and tell that they had been bribed by two of the burghers from Wroclaw, who gave them thirty marks for the deed.”
In these excerpts from a fifteenth century history, we can see that while prelates such as bishops wielded extraordinary diplomatic, military, and spiritual power, towns also had many tools at their disposal, and were not afraid to resort to violence to protect their interests. The inquisition was not a common event in the late medieval period, but they did happen. In Wroclaw itself, during a visit by Franciscan arch-zealot and future saint John Capistrano in 1451, the population was whipped into a frenzy and engaged in a ‘bonfire of the vanities’ and a vicious anti-Jewish pogrom at the instigation of the traveling cleric. Such disruptions were not welcomed by town authorities, who could find their own head on a pike as the result, which helps explain the extreme measures they were willing to take, up to and including assassination, to prevent the bishop and his inquisitor from establishing control.
 Hans Delbrück, [translation 1982], History of the Art of War, Volume III, The Middle Ages. Translated by Renfroe, Walter. Westport, Conn.: Greenwood. p. 369-372. ISBN 0803265859.
 Aloys Schmidt: Zur Mainzer Stiftsfehde 1462, in: JbBistumMainz 3, 1948, pg. 89–99
 This is all from the Maurice Michael translation IM Publications, UK, (1997) ISBN 1 901019 00 4
 See Antisemitism: A Historical Encyclopedia of Prejudice and Persecution, Volume 1, Richard S. Levy, (ABL-CLIO, 2005), page 96