The Crusades were a series of Christian efforts to wrest Jerusalem from the Muslims. On their way, the frenzied mobs wreaked havoc on numerous Jewish communities in medieval Western Europe. Read on for 11 facts about this horrific era of history, which set the precedent for countless Antisemitic acts carried out since then in the name of religion.

1. The Crusades Were “Holy” Wars

The Crusades were a series of “holy” wars carried out by European Christians primarily in the 11th-13th centuries. Their stated goal was to free Jerusalem from the Muslims, whom they viewed as infidels, and establish a Christian kingdom there. On their way to the Holy Land, the zealous mobs pounced on the opportunity to rid themselves of the “infidels” in their midst—the Jews—viciously decimating many Jewish communities.

Read: The Bloody Crusades

2. They Were Initiated by Popes

Far from being a grassroots movement, the Crusades were called for and directed by the Popes themselves. Although they did not openly advocate for the murder of Jews, many church leaders were quick to turn a blind eye when these atrocities did occur.

3. The Crusaders’ Motives Were Far From Sacred

Politics played a large role in the papal decision to launch a crusade. For centuries, the Church had been at odds with the monarchs of Western Europe, each side jockeying for power. What greater strategy to undermine royal authority than to call for a religious war, uniting the masses under the Pope’s banner? As for the soldiers, they joined the Crusades as an easy way to get rich off plunder—and to obtain the Church’s promise of eternal salvation and automatic forgiveness for all their sins.

Read: 10 Anti-Semitic Myths

4. Soldiers Were Joined by Mobs of Peasants

Initially, the plan was for the Crusades to consist of armies of professional soldiers on an organized expedition to the Holy Land. But as religious hysteria spread throughout Europe, more and more peasants and commonfolk joined the Crusaders’ ranks. With tens of thousands of people joining the cause, any sense of order and discipline had now disappeared, and the masses, spurred by religious zeal and natural greed, felt free to act as they wished. In many cases, these mobs overwhelmed the forces of local rulers who attempted to protect their Jewish subjects.

5. The First Was the Worst

Jews were pillaged and murdered during each of the first three Crusades. In terms of casualties and mass destruction, the First Crusade surpassed the others. Initiated in 1096 by Pope Urban II, the victims of this crusade included Jewish communities in France, Germany, and Jerusalem.

Read: The Martyrs of Blois

6. The Rhineland Was Hit Hard

After wreaking havoc on various communities in France, the armies of the First Crusade made their way to Germany. What followed was a bloodbath in the three great Jewish communities of the Rhineland: Speyer, Worms, and Mainz.

Throngs of Crusaders entered Speyer on Shabbat, 8 Iyar, where they proceeded to murder 10 Jews for refusing to embrace Christianity. The rest of the community was saved thanks to the intervention of the local ruler.

Read: What Does the Jewish Last Name Shapiro Mean?

The Jews of Worms and Mainz did not fare as well. When news of the onslaught reached the community of Worms, many Jews barricaded themselves in the ruler’s castle for protection. The mob arrived there on 23 Iyar, finding easy prey in the Jews who had remained in their homes. Seven days later, the Crusaders penetrated the fortress and murdered the Jews inside. By the time they had left, the bulk of the community—800 souls in all—had been ruthlessly slaughtered, with the rest forcibly baptized.

The Jews of Mainz similarly sought safety in the ruler’s castle, only to have the Crusaders storm the walls on 3 Sivan, resulting in the deaths of the 1,300 Jews hiding inside.

These cities were the first of many in Germany attacked by the frenzied mobs, who murdered the Jewish inhabitants, ransacked their homes, and desecrated their Torah scrolls.1

Read: 17 Facts About Ashkenazi Jews

7. Many Jews Sacrificed Their Lives Rather Than Convert

In many instances, the Crusaders promised to spare the Jews’ lives if they would agree to convert. The vast majority categorically declined the offer and proudly chose death over denouncing their faith. In some cases, Jews took their own lives and those of their children to prevent them from being forcibly baptized.2

Read: What Is the Jewish View on Martyrdom?

8. Rabbeinu Tam Survived the Second Crusade

The Second Crusade, launched in 1146, inflicted further losses on the Jewish communities of France and Germany. In one instance, bloodthirsty crusaders entered the home of Rabbi Yaakov ben Meir, commonly known as Rabbeinu Tam, in the French town of Ramerupt. After pillaging his home, they stabbed him multiple times in the head. Miraculously, at the last moment, he was saved thanks to the intervention of a passing nobleman.3

Read: Rabbeinu Tam

9. English Jews Suffered From the Third Crusade

In 1189, Richard the Lionhearted was crowned king of England and announced his intent to join the Third Crusade. This declaration fanned anti-Jewish sentiment among the populace, who proceeded to target several English Jewish communities. Notable among them was the Jewish community of York, where 150 Jews, under siege at Clifford’s Tower, met a tragic death.4 Although there is no reliable source for the custom, Jews traditionally have not lived in York, or even spent a night there, since the massacre.

Watch: The Life and Times of Rabbi Yom Tov of York

10. They Set a Dangerous Precedent

The total number of Jewish casualties from the First Crusade is estimated at about 10,000—a far cry from some of the later tragedies our people underwent (most notably the Holocaust). However, the population of Europe in 1096 was less than 10% of what it is today, and the numbers given above represent entire communities that were decimated.

More importantly, the Crusades marked the first organized massacres of Jews in the Christian world. While medieval Jews had been persecuted before, those events were sporadic and contained. With the advent of the Crusades, anti-Jewish sentiments became popularized among the masses, resulting in innumerable blood libels, incarcerations, murders, and expulsions—including the ugly face of Antisemitism we see rising today.

Read: The Rebbe on How (Not) to Combat Anti-Semitism

11. They Are Commemorated in Jewish Life

The Crusade massacres endure in Jewish custom and liturgy until today. Many elegies were written by contemporary scholars, some of which have been incorporated into the Tishah B’Av kinnot. One example is Mi Yiten Roshi Mayim (“O that my head would be a fountain of tears!”), composed by Rabbi Klonimus ben Yehuda.

The Av Harachimim prayer, beseeching G‑d to avenge the blood of those killed to sanctify His name, is recited on Shabbat mornings before the Musaf prayer. It is skipped, however, on Shabbat Mevarchim, the last Shabbat of the month, when we “bless” the upcoming month—an occasion more attuned to positive sentiments. However, it is not skipped on Shabbat Mevarchim Sivan (and in some communities, Shabbat Mevarchim Iyar), the month(s) in which most of the Jewish victims of the First Crusade met their deaths.5

Additionally, the 20th of Sivan is a non-obligatory fast day kept to commemorate the martyrs of the Crusades (among other reasons).

Read: Why the Fast on 20 Sivan?