David, Star of

(“Shield of David”). Jewish symbol composed of two overlaid equilateral triangles that form a six-pointed star. It appears on synagogues, tombstones, and the flag of Israel. An ancient sign not much used by Jews before the Middle Ages, it was popularized by Kabbalists for protection against evil spirits. The Jewish community of Prague adopted it as an official symbol and its use became widespread in the 17th century. Though it has neither biblical nor Talmudic authority, it became a nearly universal emblem of Judaism in the 19th century. The Nazis' use of it to identify Jews invested it with the symbolism of martyrdom and heroism.