Margraviate of Brandenburg
...that the medieval Margraviate of Brandenburg was called "the sandbox of the Holy Roman Empire"?
...that the medieval <b id="mw9g"><a href="./Margraviate_of_Brandenburg" id="mw9w" rel="mw:WikiLink" title="Margraviate of Brandenburg">Margraviate of Brandenburg</a></b> was called "the <a href="./Sandpit" id="mw-A" rel="mw:WikiLink" title="Sandpit">sandbox</a> of the <a href="./Holy_Roman_Empire" id="mw-Q" rel="mw:WikiLink" title="Holy Roman Empire">Holy Roman Empire</a>"?