Matzah in the context of "Cracker (food)"

Leopoldstadt (German pronunciation: [ˈleːopɔldˌʃtad] ; Viennese: Leopoidstod; "Leopold-Town") is the 2nd municipal district of Vienna (German: 2. Bezirk) in Austria. As of 1 January 2016, there are 103,233 inhabitants over 19.27 km (7 sq mi). It is situated in the heart of the city and, together with Brigittenau (20th district), forms a large island surrounded by the Danube Canal and, to the north, the Danube. It is named after Leopold I, Holy Roman Emperor. Due to its relatively high percentage of Jewish inhabitants before the Holocaust (38.5 percent in 1923), Leopoldstadt gained the nickname Mazzesinsel ('Matzo Island'). This context was a significant aspect for the district twinning with the New York City borough Brooklyn in 2007.

Blood libel or ritual murder libel (also blood accusation) is an antisemitic trope which falsely accuses Jews of murdering Christians in order to use their blood in the performance of religious rituals. Echoing very old myths of secret cultic practices in many prehistoric societies, the claim, as it is leveled against Jews, was rarely attested to in antiquity. According to Tertullian, it originally emerged in late antiquity as an accusation made against members of the early Christian community of the Roman Empire. Once this accusation had been dismissed, it was revived a millennium later as a Christian slander against Jews in the medieval period. The first examples of medieval blood libel emerged in the Kingdom of England in the 1140s, before spreading into other parts of Europe, especially France and Germany. This libel, alongside those of well poisoning and host desecration, became a major theme of the persecution of Jews in Europe from that period down to modern times.

Blood libels often claim that Jews require human blood for the baking of matzos, an unleavened flatbread which is eaten during Passover. Earlier versions of the blood libel accused Jews of ritually re-enacting the crucifixion. The accusations often assert that the blood of Christian children is especially coveted, and historically, blood libel claims have been made in order to account for the otherwise unexplained deaths of children. In some cases, the alleged victims of human sacrifice have become venerated as Christian martyrs. Many of these – most prominently William of Norwich (1144), Little Saint Hugh of Lincoln (1255), and Simon of Trent (1475) – became objects of local cults and veneration; the cult of Hugh of Lincoln gained the support of Henry III and his son Edward I, giving it official credibility and helping it to be particularly well remembered. Although he was never canonized, the veneration of Simon was added to the General Roman Calendar. One child who was allegedly murdered by Jews, Gabriel of Białystok, was canonized by the Russian Orthodox Church.