Under Napoleon, France became by far the preeminent power on the continent during the first decade of the nineteenth century, scoring major victories over both Austria and Prussia. Napoleon controlled Europe essentially through a series of shifting alliances with major powers and by crowning his siblings as puppet rulers. One example of the latter policy was his appointment of his brother Joseph as King of Naples and Sicily, and later Spain and Portugal. Napoleon also reorganized the remnants of the Holy Roman Empire into the Confederation of the Rhine, establishing a protectorate over the loose organization of German states. Predictably, Napoleon often struggled to assert his will over Europe, as his failed attempt to keep first Portugal and then Russia in the Continental System, an embargo against Great Britain demonstrates.