The image of a vicious Jew with a large, hooked nose has long been a mainstay of anti-Semitic caricature, and remains so today. Before the year 1000, however, Jews in European artwork had no distinctive physical features, although there was no shortage of works depicting them as conniving, wicked, or dangerous. According to Sara Lipton, this all changed in the 13th century, not because someone noticed Jews with large noses, but because the hooked nose symbolized Jewish depravity:
For the rest of the [12th] century, and for several decades beyond, the shape of Jews’ noses in art remained too varied to constitute markers of identity. That is, Jews sported many different kinds of “bad” noses—some long and tapering, others snout-like—but the same noses appeared on many “bad” non-Jews as well, and there was no single, identifiable “Jewish” nose. By the later 13th century, however, a move toward realism in art and an increased interest in physiognomy spurred artists to devise visual signs of ethnicity. The range of features assigned to Jews consolidated into one fairly narrowly construed, simultaneously grotesque and naturalistic face, and the hook-nosed, pointy-bearded Jewish caricature was born. This image served many purposes. In being so fleshily vivid and realistic, the Jew’s face seemed to embody for Christian viewers the physical, secular, material world, a realm with which Jews had long been associated in Christian polemic.
Read more on New York Review of Books: http://www.nybooks.com/blogs/gallery/2014/nov/14/invention-jewish-nose/