Sanssouci Picture Gallery
...that the Sanssouci Picture Gallery is the oldest extant museum built for a German ruler?
...that the <b id="mwBtE"><a href="./Sanssouci_Picture_Gallery" id="mwBtI" rel="mw:WikiLink" title="Sanssouci Picture Gallery">Sanssouci Picture Gallery</a></b> is the oldest extant <a href="./Museum" id="mwBtM" rel="mw:WikiLink" title="Museum">museum</a> built for a <a href="./Germany" id="mwBtQ" rel="mw:WikiLink" title="Germany">German</a> ruler?