The Qadi, Ahmed b. Talib (9th century), compelled the dhimmis to wear upon their shoulder a patch of white cloth (riqa') that bore the image of an ape (for the Jews) and a pig (for the Christians), and to nail onto their doors a board hearing the sign of a monkey (p. 142).
[Muslims reviled Christians for eating pork, which they, like the Jews, considered unclean. According to the Koran (2:65), Jews were transformed into apes on account of' their sins. See also: "Whomsoever God has cursed, and with whom He is wroth, and made some of them apes and swine, and worshippers of idols . . ." (Koran 5: 65), which was considered by Muslirn commentators on the Koran to refer to Jews and Christians. Translator's note - P.B.F.]
al-Maliki (11th Century), Riyad an Nufus (Bibl. Nat., Paris: Ms. Arabe 2153, Vol. 52v), In H. R. Idris
Source: Bat Ye'or, The Dhimmi. Rutherford: Fairleigh Dickinson University Press, 1985.