The Grand Duchy of Luxemburg was a revival of an ancient state which had lost its existence during the French Revolution. Although it was placed under the rule of the King of the Netherlands, a descendant of its former sovereign, it was not incorporated in his kingdom, but retained its own identity and gave to its ruler the secondary title of Grand Duke of Luxemburg. The position it occupied after 1815 was in some ways anomalous; for lying as it did between the Meuse and the Rhine, and possessing in the town of Luxemburg a fortress whose natural strength some competent critics reckoned as second only to that of Gibraltar among the fortresses of Europe, it was considered to be an indispensable link in the chain of defences of Germany against French aggression. Not being able to trust the Dutch to hold this great fortress against the French, the Congress of Vienna laid down as a principle that all land between the Meuse and the Rhine must be held by Prussian troops on behalf of the newly formed Germanic Confederation. Thus Luxemburg was held by Prussian troops on behalf of this foreign confederation, and over this garrison the only right allowed to the Grand Duke, the sovereign of the country, was that of nominating the governor. This strange state of affairs was not modified by the Belgian Revolution of 1830; for though more than half the Grand Duchy threw in its lot with Belgium to form the modern province of Belgian Luxemburg, the Grand Duchy, confined to its modern limits, still contained the great fortress with its garrison of Prussian troops. It is not surprising that, under these circumstances, the Grand Duchy joined the Prussian _Zollverein_, and so drew nearer to Germany, in spite of the independent character of its inhabitants, who have strenuously resisted any attempt at absorption into Germany. France naturally continued to cast envious eyes upon the small state with the powerful citadel, but no opportunity presented itself for reopening the question until 1866. In that year Napoleon III had anticipated that the war between Prussia and Italy on one side and Austria and the small German states on the other would be long and exhausting, and would end in France imposing peace on the weary combatants with considerable territorial advantage to herself. His anticipation was entirely falsified; the war lasted only seven weeks and Prussia emerged victorious and immensely strengthened by the absorption of several German states and by the formation of the North German Confederation under her leadership. This, the first shattering blow which the French Emperor's diplomatic schemes had received, led him to demand compensation for the growth of Prussian power, and one of his proposals was the cession of Luxemburg to France.