In 1848, seven years after the conclusion of these negotiations, Europe was thrown into convulsions by the appearance of a new era of revolution. France became a republic, and Germany, Austria, and Hungary went through such violent upheavals that the existence of arbitrary government hung for a time in the balance. Out of the struggle emerged Napoleon III, of France, who thought some military achievement was necessary to stabilize his power. At that time Russia was asserting a protectorate over all Christians in Turkey, and it was generally believed that she was about to establish vital political control. Napoleon took up the sword against her and Great Britain came to help, the result being the Crimean War, 1854-1856. In the beginning of this struggle the Concert of Europe seemed to be dead, but two years of heavy fighting and nearly futile losses brought it to life again. The war, which began in an outburst of international rivalry, ended in the Conference of Paris, 1856, in which all the Great Powers but Prussia undertook to settle the Eastern question by neutralizing the Euxine and the Danube and by making new allotments of territory which were supposed to adjust boundaries in such a manner that rivalries would disappear. The Conference went on to take up the work of a true European congress by agreeing upon the Declaration of Paris, in which were assembled a body of rules regulating neutral trade in time of war. England gave up her long defended pretension to seize enemy goods on neutral ships and neutral goods on enemy ships, and in return gained the recognition that privateering was unlawful. Thus the Crimean War, fought by Great Britain and France against Russia, and in support of Turkey--with Austria and Prussia as neutrals--was at last ended by an agreement between all the parties concerned. The nations undertook to settle the long Eastern dispute by pledging the sultan to reforms which it was not in his nature to carry out.