Four years later, upon the death of Martha Washington, he inherited the mansion of Mount Vernon and part of the estate.<ref>[https://books.google.com/books?id=PGlOAPYsfrcC&pg=PA320 The New international encyclopaedia, Volume 20]</ref> | Four years later, upon the death of Martha Washington, he inherited the mansion of Mount Vernon and part of the estate.<ref>[https://books.google.com/books?id=PGlOAPYsfrcC&pg=PA320 The New international encyclopaedia, Volume 20]</ref> |