A reader recently emailed me asking about the origins of the Star of David, the most recognizable symbol of the Jewish people. While the Star has a long and nebulous history, its origins don't stretch back as far as its name implies.
The six-pointed star associated with Jewish culture and Israeli independence doesn't actually have much to do with King David.
Its Hebrew name doesn't even mean "star". Magen David means "Shield of David", a term that isn't directly related to the star symbol. Magen David comes from a prayer said on Shabbat and it references God, who protected David from the wrath of various enemies throughout his story. Even then, the term itself doesn't come from the bible or any of its contemporary texts. It is a poetic phrase developed in the early rabbinic age, probably in the first few centuries of the Common Era.
The earliest known representation of a star in association with Jews is a relief depicting a Babylonian king meeting the recently-defeated king of Judah. The star in the relief isn't exactly the Magen David, though. Popular use of the Star didn't really begin until the Middle Ages, around 1100 CE. At that time Kabbalistic mysticism was popular among European Jews, so they created and embraced a number of symbols to which they attributed many layers of meaning.
The Kabbalistic understanding of the Magen David revolves around the significance of the number 6. It is a six-pointed star with a prominent, open center. This is often thought to represent the six days of earthly work being supported by the holy seventh day of rest. That's why 7 is a number closely associated with God. It's the sabbath, the seventh day when all focus turns toward divinity. In the Magen David the six points emanate from the solid center, likely a metaphor for the lives of people emanating from the unseen divine.
There may be a political reason for the exact shape of the Star. Many Kabbalists adopted an older, more universal star: the Pentagram. Though it is only five-pointed, the Pentagram has been a very pervasive symbol of spirituality, its origins going back as far as the first cities on Earth. In its earliest days, the city of Jerusalem even used the Pentagram as its official seal. With the rise of Christianity in the West, old spiritual symbols were deemed unholy by the church and subsequently demonized. The church began to claim that the Pentagram was the symbol of Satan and the occult in general. The Magen David possibly grew out of a desire to distance Jews from a suddenly incriminating symbol.
As for why the Star came to be associated with King David (who was never referenced as bearing any star-symbol whatsoever), it likely has to do with the transformation of the Jewish identity in the Middle Ages. Living in diaspora required Jews to contemplate the nature of their culture. Are we just a religion or are we still a nation? If we are a nation, just how unified are we? The Magen David became a symbol of Jewish identity and, wanting to associate it with strength and divine protection, it was soon linked to David. This is certainly why it is the symbol of the Zionist movement.
Such is the nature of ancient symbolism, especially for a people who have shifted between so many different host cultures over the centuries. It is impossible to say where exactly these images and figures originate, but it is also highly unlikely that symbols like the Magen David have a single source to begin with.