On 9 January 1349, in the city of Basel on the upper Rhine, approximately six hundred Jews — the entire identified Jewish population of the city — were rounded up by the municipal guard, marched across one of the river bridges to an uninhabited island in the middle of the Rhine that had been used as a fishing landing, and locked inside a single large wooden building. The building had been built over the previous several weeks by the city’s carpenters. It had no permanent function. It had been constructed specifically to hold the people who were now inside it. Once the doors were barred from the outside, the building was set on fire. Everyone inside burned to death.
The children of the Basel Jewish community had been separated from their parents earlier that morning and forcibly baptized into Christianity. They were distributed to Christian foster families. They were not allowed to inherit any of their parents’ property, which was seized by the city and used to pay off debts that prominent Basel families had owed to Jewish moneylenders.
The plague — the Black Death whose imminent arrival had been the official justification for the massacre — would not reach Basel for another four months. By the time it did, the city’s Jewish community no longer existed. The plague killed roughly a quarter of the city’s remaining Christian population. The Jews who had been blamed for it had been dead for most of a year.
The Basel massacre was, as far as the documentary record allows us to reconstruct, the first of the major organized Black Death pogroms in the German-speaking world. The Strasbourg massacre five weeks later followed the same pattern in nearly every detail. Over the following two years, identical events were repeated in approximately three hundred towns and cities across the Rhineland, southern Germany, Austria, Bohemia, and northern Italy. The total Jewish dead is estimated at between forty and seventy thousand. It was the largest single-event massacre of Jews in Europe before the twentieth century.
What the documentation says
The principal contemporary source is the Basler Chronik, an anonymous fifteenth-century chronicle of the city that incorporates earlier annalistic material from the time of the massacre itself. The Chronicle is preserved in the Basel state archive. The account of January 1349, in the older annalistic source the chronicler used, runs to roughly two pages.
The political pattern is unambiguous and matches Strasbourg. The Bishop of Basel, Johann Senn von Münsingen, had taken a position throughout the autumn of 1348 — following the bulls of Pope Clement VI in Avignon — that the Jewish community was not responsible for the plague and was not to be molested. The city council had backed him. The pressure to act against the Jewish community came from the city’s craft guilds, which were in the same period engaged in a political struggle to break the patrician monopoly on municipal government.
The crisis began in November 1348, when reports of the plague’s arrival in Marseille and Avignon began circulating through the Rhine valley. The Basel guilds organized a series of mass demonstrations demanding action against the Jewish community, which they accused of having poisoned the wells. The Bishop and council refused. The guilds, in response, conducted a brief and effectively bloodless coup in late December 1348. The Bishop was forced to leave the city. The patrician councilors were forced to resign or to agree to new policies. A new council was constituted with substantially expanded guild representation.
The new council’s first major action, on 8 January 1349, was the decree ordering the seizure of all members of the Jewish community for execution the following day. The execution was carried out on the morning of 9 January.
The new council also issued, on the same day, a permanent expulsion order for any Jewish person who might return to Basel. The order was to remain in force for two hundred years. The next Jewish community in Basel was not established until the late sixteenth century, and that one was repeatedly expelled and re-readmitted over the following two centuries.
Why an island in the river
The choice of the river island as the execution site is striking and was unusual for the genre. Most Rhineland massacres of 1349 took place in city cemeteries (as at Strasbourg), in main squares, or in the Jewish quarters themselves. The Basel decision to construct a purpose-built wooden building on an uninhabited Rhine island, isolated from the city by water, was deliberate.
The most probable explanation, accepted by Lotter and by other modern historians who have worked on the Basel case, is fire control. The Basel city council in early January 1349 was a new and politically unstable institution that had just executed a coup against the previous administration. It needed the massacre to be perceived as orderly and contained, not as a mob action. A building full of burning people in the middle of a wooden city — Basel at the time was almost entirely timber-framed — would have created an immediate risk of a general urban fire. An island in the river had no such risk. The fire could be observed from the bridges and from the city walls without the danger of spreading.
A secondary explanation, also plausible, is acoustic isolation. The wooden building was several hundred meters from the nearest occupied dwelling. The sounds of the execution — and there would have been sounds — were partly muffled by the Rhine’s running water and by the distance. The city’s surviving residents could be aware of what was happening without being forced to be direct witnesses. This was, in the careful phrasing of one modern Swiss historian, an administrative execution rather than a popular one.
The new council, having carried out the massacre, governed Basel for the rest of the fourteenth century. The guild reforms it had achieved became permanent features of Swiss municipal governance and are sometimes cited as part of the institutional background of the later Swiss Confederation. The Bishop Johann Senn von Münsingen never returned to Basel; he spent his remaining years in his rural episcopal estate at Pruntrut and died in 1365.
What survives
The Rhine island where the wooden building stood was eventually built up as part of Basel’s industrial waterfront in the nineteenth century. It is now a small port area called the Klybeck. There is no marker indicating the site of the 1349 building, and the exact position within the modern industrial area is no longer identifiable from the medieval descriptions.
The Bishop Johann Senn von Münsingen’s tomb is in the cathedral of Basel, on the southern wall of the chancel. The inscription gives his dates and his title. It does not mention the events of January 1349.
A small bronze plaque was installed at the entrance to Basel’s medieval Jewish quarter on the Andreasplatz in 2009, on the 660th anniversary of the massacre, by a joint committee of the Basel-Stadt cantonal government and the city’s modern Jewish community. The plaque, in German and Hebrew, names the date and the number of dead. It does not name the city council members who ordered the execution. The names are in the Basler Chronik, in the relevant entry, in the city archive. They are available to anyone who wants to find them.