Pentagram and Magen David

M. Costa in his (Hebrew) book "Hatakh ha-zahav, hotam Shelomoh u-Magen-David" (Poalim, 1990) claims that there was no clear distinction between the pentagram and the Magen David until the 20^th century.

 

After giving a lecture about this subject one of his pupils told him that there's a Midrash (interpretation of the Holy Scriptures) that connects the pentagram and the Magen-David. The Midrash explains that the Magen David was meant to pass from father to son for generations, but King Solomon was too modest to inherit his father's emblem and chose a less honorable one by taking off one of the sides of the Star of King David and by that he created his own (Solomon's) seal...