The Star of David is also called the Shield of David. It did not emerge as a symbol of Judaism until the Middle Ages and was not popularly associated with Judaism until after World War II. Prior to its association with Judaism, it was also associated with Christianity and Islam.
It is not clear how the Star of David originated. Furthermore, the symbolic meanings of it vary. Some believe the points of the two triangles represent different cardinal directions. Others believe it represents the relationship between God, the Torah and Israel. Still others believe the opposing triangles represent good and evil.
Although it is named for King David, the Star of David has not always been associated with David. For a time, it was associated with David's son, Solomon. The name "Shield of David" originates from a Jewish legend about the design of David's shield, which involved two interlocking triangles. It was only after Hitler forced the Jewish people to wear Stars of David to identify themselves during World War II that the symbol became widely associated with the Jewish faith. After the war, the newly founded nation of Israel adopted the symbol and made it part of their official flag.