"Jud Lew is the name (or possibly pseudonym) of a 15th century German fencing master. The appellation "Jude" seems to signify that he was Jewish, though Jude was also a surname of some non-Jewish families, and he seems to have stood in the tradition of Johannes Liechtenauer, though he was not included in Paulus Kal's ca. 1470 list of the members of the Fellowship of Liechtenauer.
Lew is often erroneously credited with authoring the Cod. I.6.4º.3, an anonymous compilation of various fencing treatises created in the 1460s. In fact, his name is only associated with a single section of that book, a gloss of Johannes Liechtenauer's Recital on mounted fencing that is one branch of the so-called Pseudo-Peter von Danzig gloss (see below). Though some versions of Martin Huntfeltz's treatise on armored fencing are also attributed to Lew, this is almost certainly an error. By convention, the gloss of Liechtenauer's Recital on long sword fencing that generally accompanies this mounted gloss is also attributed to Lew." https://wiktenauer.com/wiki/Jud_Lew