So I ordered a blue and white flag with the Shield of David painted upon it. That is how the national flag, that flew over Congress Hall, came into being. The standard name for the geometric shape is a hexagram or six-pointed star, composed of two interlocking equilateral triangles. One of the first Jewish uses of the Star of David was as part of a colophon, the special emblem printed on the title page of a book. The idea was to differentiate this printer's books from those of his competitors and to embellish the title page.
Colophons are as old as the printing press itself.
According to Sholem, the motive for the widespread use of the Star of David was a wish to imitate Christianity. During the Emancipation, Jews needed a symbol of Judaism parallel to the cross, the universal symbol of Christianity. In particular, they wanted something to adorn the walls of the modern Jewish house of worship that would be symbolic like the cross. This is why the Star of David became prominent in the nineteenth century and why it was later used on ritual objects and in synagogues and eventually reached Poland and Russia. The pursuit of imitation, in Sholem's opinion, led to the dissemination of an emblem that was not really Jewish and conveyed no Jewish message.