I've just read the Wikipedia page on Medieval Antisemitism. Some of the stuff on there reinforces my thinking on the subject;
From around the 12th century through the 19th there were Christians who believed that some (or all) Jews possessed magical powers; some believed that they had gained these magical powers from making a deal with the devil.Very witchy/wizardy.
The story of Little Saint Hugh of Lincoln (d. 1255) said that after the boy was dead, his body was removed from the cross and laid on a table. His belly was cut open and his entrails were removed for some occult purpose, such as a divination ritual. [my emphasis].Of course, the Druids were accused of exactly the same thing. Blood libel/human sacrifice.
The Fourth Lateran Council in 1215 was the first to proclaim the requirement for Jews to wear something that distinguished them as Jews (and Muslims the same). It could be a coloured piece of cloth in the shape of a star or circle or square, a Jewish hat (already a distinctive style), or a robe.A man in a pointed hat and robe, decorated with a star, square or circle. It's hard not to think Merlin.