David Alroy

In the twelfth century, (according to the Hebrew Wikipedia), David Alroy, who was born as Menahem Ben Shlomo Alroy, proclaimed that he was the Messiah. He founded in Khazaria a Messianic Jewish movement that intended to conquer Palestine. He used the Star of David as his emblem. Since his name is the same name as of King David and King Solomon there is a theory that this symbol started to spread not from the times of the first Jewish Temple but from the twelfth century.