The following paragraph is from Dr. Asher Eder’s book The Star of David, which was published in 1987 in English in Jerusalem by Rubin Mass Ltd. The publication here is courtesy of Oren Mass
This version includes corrections and new materials that do not appear on the printed version
In the meantime, before the end of the Thirty Year War, the Jewish community of Prague began to employ a seal showing the hexagram with the six Hebrew characters מגן דוד , Magen David , inscribed in its six angles, for the first time officially combining the design and the term.Also in Bohemia, the synagogue of Budweis is known as having displayed the Magen David during those centuries.It was also in Prague that the first Hebrew book ever published in modern book form, the Seder Tefillot, appeared in 1512, with a six-pointed star as the printer's mark and bearing an inscription which says: "Every man under the banner of his father's house....may they be worthy of good gifts, all those who adhere to the Magen David" The transition from the "internationality” of the hexagram to the Jewish Magen David, or Shield of David, was not smooth. On the one hand, Christians and Jews alike used it on amulettes throughout the Middle Ages, but on the other hand there were incidents of persecution of Jews who used it. One such incident involving the six-pointed star occurred in Brandenburg, Germany in the 16th Century. There, a mint master by the name of Lippold struck the coinage of Prince Elector Joachim II, using hexagrams as printer marks on the reverse side of the coins.
Lippold's coin 1567
After Joachim IInd's death, this was one of the accusations which led to the mint master's execution on the rack. Then, in Moravia, a province neighboring Bohemia, the leaseholder of the mint in Wischnau was dismissed because he, too, used the hexagram as his mint mark.
These incidents may indicate that besides the emperor, non-Jewish circles had also begun to recognize a special connection between the hexagram and the Jews.Apparently, it reached Vienna through other communities in Bohemia: Viennese Jews are known to have used it on their community's seal in 1655. Better known is the boundary stone of 1656, with the six-pointed star marking the site of the Jewish cemetery, and the cross marking the site of the neighboring Carmelite monastery.Then we find it in printers' marks on several Jewish books, including an Italian edition of the Rambam's Guide to the Perplexed (Printed at Sabbioneta in 1553). It is shown in tree leaves and is obviously linked to those Psalms which mention the Lord as a shield.In the following centuries, many European Jewish communities adopted the star as their symbol, among them the Ashkenazi synagogue of Amsterdam (in 1671), which showed it on their building and on cult objects and books.The 17th-Century Shabtai Zvi movement provided a new interpretation of the symbol, namely, The Seal of MBD, these letters standing for Messiah Ben David, relating the hopes for the final redemption by the Son of David. The linking of the Magen David to such widespread yearnings for redemption from the torment of anti-Semitism, as well as the need for a sign of self-identification in a world where every other group had an emblem of its own, must have been an added impetus for Jewish circles all over the world to adopt this symbol.All this can be linked to a passage in an ancient prayer, our daily Amidah-prayer, which reads in its English translation: "Let the Branch of David thy servant shoot forth speedily...". Similar also is our special prayer on new moon days, alluding to the Son of David.