||The name its-self comes from this story (and that' why the translation "Roter Schild" is not quiet correct):
Mayer Amschel Rothschild (* 23. February 1744; 19. September 1812 in Frankfurt/Main, Germany) was the founder of the Rothschild-dynasty. Its ancestors lived here since the middle of 16th Century in the Jewish Getto of the city Frankfurt, the Jew lane.
The houses in the Jew lane were not described by house numbers, but by multi colour or special registered trade marks characterized. Since the family lived over generations in "the house to the red sign", which means "Schild" in German, the surname "Rothschild" was already established in 17. Century . It wasn't changed, when the Rothschild's moved into the house to the Hinterpfann. Mayer Amschels father, Amschel Moses Rothschild, operated a business for trading with small goods and money exchanges in Jew lane.
Today in modern German we don't use "roth" for red but "rot" (which means red) - the "h" has been lost since the middle-ages