||A volume of pentitential prayers that were established to commemorate the terrible Chmelnitzky pogroms of 1648 in Poland, and were renewed with certain changes for Hungary following the Holocaust. The prayers were arranged and published with the agreement of the Central Office for the Congregations of the Yeraim (Orthodox congregations) of "our country" [Hungary] in memory of those Jews killed from 1941 and onwards, and especially in 1944 and 1945, and for the destruction of synagogues, houses of study, Torah scrolls and Holy Books. It also contains the order of prayers for a fast day and laws for Hungarian Jews, based on Warsaw (1880), with the omission of the Kel Maleh Rahamim of R. Yechiel Michel, and with the addition of Selichot from the Selichot of the rest of the year.
In 4931 (1171) there was a terrible blood libel in France that led to the execution by sword and fire of 31 Torah scholars who were first given the choice of forsaking their Judaism. This episode was but a part of the tragic events of the Crusades that had begun in 1096. Rabbeinu Tam declared the 20th of Sivan as a day of fasting "greater than Tzom Gedalia; like Yom Kippur". Selichot and Kinot were composed for 20 Sivan to mark it. Almost 500 years later, in 5408-5409 (1648-49 – years that correspond to the Hebrew dates of "Tach v'Tat" [Taf-Chet and Taf-Tet]), the 20th of Sivan became associated with the pogroms of the Ukrainian anti-Semite, the Cossack leader Bogdan Chmelnitzky, which resulted in the deaths of many tens of thousands of Jews and the destruction of hundreds of beautiful Jewish communities. The Council of the Four Lands, a powerful rabbinic body in Eastern Europe, reiterated the decree of the 20 Sivan as a fast day. Their decree was to apply to males from the age of 18 and females from 15. Even neighboring countries not part of the council's domain accepted upon themselves the fast of the 20th of Sivan and all of its stringencies. The Shach (Rabbi Shabtai Cohen, famous commentator on the Shulchan Aruch), added strength to the fast day by declaring it such, even though he was outside the boundaries of the "Four Lands."