The Twentieth of Sivan () is a historic Jewish fast day, first instituted by

Rabbeinu Tam Jacob ben Meir (1100 – 9 June 1171 (4 Tammuz)), best known as Rabbeinu Tam (), was one of the most renowned Ashkenazi Jewish rabbis and leading French Tosafists, a leading '' halakhic'' authority in his generation, and a grandson of Rashi. K ...

in 1171. It originally commemorated massacre on that date at

Blois Blois ( ; ) is a commune and the capital city of Loir-et-Cher Departments of France, department, in Centre-Val de Loire, France, on the banks of the lower Loire river between Orléans and Tours. With 45,898 inhabitants by 2019, Blois is the mos ...

in France, the first blood libel in continental Europe. It also came to represent other anti-Jewish violence during the Crusades era, such as the

Rhineland massacres The Rhineland massacres, also known as the German Crusade of 1096 or ''Gzerot Tatnó'' (, "Edicts of 4856"), were a series of mass murders of Jews perpetrated by mobs of French and German Christians of the People's Crusade in the year 1096 ( ...

. The day was later also marked to commemorate the Cossack riots of 1648–49 in Poland-Lithuania, instituted by the

Council of Four Lands The Council of Four Lands (, ''Va'ad Arba' Aratzot'', ) was the central body of Jewish authority in the Polish–Lithuanian Commonwealth from the second half of the 16th century to 1764, located in Lublin. The Council's first law is recorded as h ...

in 1650, taking the coinciding date of an early attack on the Jews of

Nemyriv Nemyriv ( ; ) is a historic city in Vinnytsia Oblast (province) in Ukraine, located in the historical region of Podolia. It was the administrative center of former Nemyriv Raion (district). Population: Nemyriv is one of the oldest cities in Vin ...

in 1648. After World War II, suggestions were made to observe it as a Holocaust memorial day, but this was not widely adopted; it was particularly supported for a time by rabbis in marking the mass deportations from Hungary to Auschwitz of May-June 1944. In 1948, Tzvi Pesach Frank proposed to use the day to commemorate the fall of the

Jewish Quarter Jewish Quarter may refer to: *Jewish quarter (diaspora), areas of many cities and towns traditionally inhabited by Jews *Jewish Quarter (Jerusalem), one of the four traditional quarters of the Old City of Jerusalem *Jewish Quarter (), a popular name ...

in the

Battle for Jerusalem The Battle for Jerusalem took place during the 1947–1948 civil war in Mandatory Palestine, 1947–1948 civil war phase of the 1947–1949 Palestine war. It saw Jewish and Arab militias in Mandatory Palestine, and later the militaries of Isra ...

. Some communities still recite the

Selichot Selichot (, singular: , ''səliḥā'') are Jewish penitential poems and prayers, especially those said in the period leading up to the High Holidays, and on fast days. The Thirteen Attributes of Mercy are a central theme throughout these pra ...

service for the occasion.The selichot service can be foun
here
in the Kol Bo machzor. For another version of the Selichot, se
Kuntres Posen
They are recited today by Belz Hasidim, Skver Hasidim and Papa Hasidim.

References

{{reflist Medieval anti-Jewish pogroms Jewish fast days Sivan observances Ashkenazi Jews topics Anti-Jewish pogroms in Europe Blois Antisemitism in France History of Centre-Val de Loire 1171 in Europe 1170s in France