The first historical evidence of Star of David is referred to the third century A.D. and it was found on the tombstone in Italian city of Taranto. In literature it's not mentioned until the twelfth century A.D. and it was first found only in the Eshkol ha-Kofer of the Karaite Judah Hadassah (12th century literary Hebrew piece):
Hebrew historians note that the Star of David appeared on Jewish amulets approximately in the twelfth century. It was signed on amulets on the hand with other symbols such as pentagrams, stars, the name of god in Hebrew, etc. Nevertheless it's very interesting and probably strange that pentagram, not the hexagram (the Star of David) was mostly spread in magic symbols and attributes of Jewish cult. Scientists and archeologists are not even sure if the Star of David had any similar origins in any culture of ancient Mediterranean: Hellenic or Coptic.
Some of historians assume that it might be primary used by Jewish sect of Kabbalah which adopted hexagram from Templars. Jewish sect of kabala uses David star as amulets placing it in glass spheres or using it simply as an amulet and sigh.
The spread of usage of Star of david begins in the 14th century in Jewsih communities of Europe. ...