The Star of David (מָגֵן דָּוִד) is a generally recognized symbol of both Jewish identity and Judaism. Its shape is that of a hexagram: the compound of two equilateral triangles. A derivation of the seal of Solomon, which was used for decorative and mystical purposes by Muslims and Kabbalistic Jews, its adoption as a distinctive symbol for the Jewish people and their religion dates back to 17th-century Prague. In the 19th century, the symbol began to be widely used among the Jewish communities of Eastern Europe, ultimately coming to be used to represent Jewish identity or religious beliefs. It became representative of Zionism after it was chosen as the central symbol for a Jewish national flag at the First Zionist Congress in 1897. By the end of World War I, it had become an internationally accepted symbol for the Jewish people, being used on the gravestones of fallen Jewish soldiers. Today, the star is used as the central symbol on the national flag of the State of Israel. Unlike the menorah, the Lion of Judah, the shofar and the lulav, the hexagram was not originally a uniquely Jewish symbol. The hexagram, being an inherently simple geometric construction, has been used in various motifs throughout human history, which were not exclusively religious. It appeared as a decorative motif in both 4th-century synagogues and Christian churches in the Galilee region. Gershom Scholem writes that the term "seal of Solomon" was adopted by Jews from Islamic magic literature, while he could not assert with certainty whether the term "shield of David" originated in Islamic or Jewish mysticism. Leonora Leet argues though that not just the terminology, but the esoteric philosophy behind it had pre-Islamic Jewish roots and provides among other arguments the Talmud's mention of the hexagram as being engraved on Solomon's seal ring.