A few miles downstream, east of the district Deggenau, lies the confluence of the River Isar with the Danube.

The first written mention of Deggendorf occurred in 868, and Henry II, Holy Roman Emperor established his supremacy over the area in 1002.

The first reference to this murder of the local Jews is found in an official document by Duke Heinrich XIV originating from 1336.

In this document, the duke pardoned the citizens of Deggendorf and spared them any kind of punishment for killing the Jews.

[4]: 199–202 Further clues to the murders are found, for example, in the annals of some important monasteries of the time and in the works of Johann von Viktring (d. ca.

Johann von Viktring refers to this infestation in connection to the murder of the Jews of Deggendorf.[4]: 203–221, esp.

"Im Jahre des Herrn 1337, am nächsten Tag nach St. Michaels-Tag, wurden die Juden erschlagen, die Stadt zündeten sie an, da wurde Gottes Leichnam gefunden, das sahen Frauen und Männer, da hob man das Gotteshaus zu bauen an."

[5] The fully formed legend of the host desecration by the Jews of Deggendorf and about the miracles happening after their "punishment" appears in a composite manuscript in the library of the monastery St Emmeram in Regensburg not before the 15th century.

[6]: 105f  By the beginning of the 15th century the fully formed legend had already spread far enough to encourage more and more people to pilgrimage to Deggendorf.

[4]: 506  The development of the pilgrimage to become a time of worship of the magic hosts of Deggendorf was particularly promoted by pastor Johannes Sartorius (1599–1609) and Duke Albrecht of Bavaria (1584–1666).

Due to these developments the town pursued a thorough advertising campaign combined with a redesign of the festivities in 1976 resulting in a slight increase in younger peoples’ attendance figures.

[4]: 660–661 Even though the debate quickly became a heated topic in the press – abroad as well as domestic[4]: 664  – it took until 1968 for the first four of the sixteen oil paintings to finally be removed,[4]: 689  which was the first concession.

[4]: 668–669  The diocesan chapter of Regensburg invoked the long tradition of the pilgrimage and assured that the Jews as its cause were hardly ever mentioned in the sermons.

[4]: 669–671 In the 1980s, Manfred Eder (University of Regensburg) started work on his doctoral thesis carefully researching the origin and development of the "Deggendorfer Gnad".

[6]: 102–109  In 2017, Richard Utz linked the tardy discontinuation (thirty years after the Second Vatican Council) of the pilgrimage tradition to a decision by Regensburg Bishop, Rudolf Graber.

In the late 1960s, Graber replaced a chair in Judaic Studies with one in Dogmatic Theology at the newly founded University of Regensburg.

A chair in Judaic Studies would have sped up the production of the kind of research that would have debunked the tradition's false claims.

[7] Deggendorf was the site of a displaced persons camp for Jewish refugees after World War II.