Several documents point to the first settlement of Jews in Krems in the 12th century. The Jew Ernustus is mentioned as a witness in a document from 1136.
Privileges for Jews in Krems were granted by Duke Otokar II. (1233-1278). Jews are mentioned as living there during the 1250s and 1260s of the 13th century. Krems was at that time a more important Jewish settlement than Vienna due to close economic ties with Duke Otokar. During the second half of the 13th century a Judenrichter (“Judge of the Jews”) is mentioned. There is also the first record of a Judenmeister (representative of the Jewish community), ‘Smoiel Magister Iudeorum’, in Austria. In 1264 the Jew Ismael gave a loan to two burghers of Krems. The Jewish community of Krems also boasted a yeshiva.
In 1293 a blood libel led to the murder of two poor Jews, while the more prosperous ones could buy themselves free. In 1349 a mob from Krems and neighboring villages attacked the Jews of Krems, murdered many of them and plundered their houses. Some Jews were able to escape to the castle; others burnt themselves in their houses. In 1355 Jews were again living in Krems.