Jews were expelled from Bohemia in 1541, and from Austria in 1544, 1572 and 1602, for collaboration with the Turks. This woodcut, by artist Hans Burgkmair, shows that our ancestors were well aware of the ties between Jew and Muslim. The image served as a frontispiece to a book called Dialogus de Diversarum Gentium Sectis at Mundi Religionibus, published in 1508. Written in Latin by Dr. Oliverius, it featured an imaginary dialogue between people of different religions, in the course of which the Muslim and Jewish representatives were persuaded to convert to Christianity.
In the image, the central female figure represents the Christian church. On the left, there are two female figures representing Muslims (Saracena) and Jews (Sinagoga). What is interesting is that the Muslim holds up a flag on which a picture of a Jewish hat appears, while the Jewess holds up a flag with the word "Machometus" on it. In other words, it was known that Jews and Muslims were united in an unholy alliance against Christianity.
Here is a zoomed in version below.
Pages 115 to 117 of the book "The Jew as Ally of the Muslim" are reproduced below. You may have to zoom in on these images to read the text properly.