The difficulties in the way of Italian unification were manifold. For our purposes, however, we are not interested in them or in the means by which they were overcome beyond the fact that they finally were overcome, and that as early as 1859 a large number of the different Italian states had been united with the assistance of Napoleon III under the rule of Victor Emmanuel II, originally King of Sardinia and Piedmont. In that year, however, after Austria had been driven out of Lombardy through the combined efforts of Italian and French troops, Napoleon III suddenly arrived at an understanding with Francis Joseph, and peace was concluded between France and Austria. This left in the hands of the Austrians still an important part of northern Italy known as the Quadrilateral. Rome, too, and a considerable territory surrounding it, known as the Papal State, was not included in the newly formed kingdom of Italy, the pope refusing to give up his temporal powers and Napoleon III supporting him in that refusal to the extent of maintaining French troops in Rome. The Austro-Prussian War of 1866, as we have already shown, had important results for Italy. For previous to its breaking out Prussia had concluded a treaty with Italy, and when hostilities began between Austria and Prussia, Italy immediately attacked her old enemy. When peace was concluded between Prussia and Austria, Prussia insisted, in order to reward her southern ally, that Austria should relinquish practically all of her Italian possessions. Four years later, in 1870, the outbreak of the Franco-Prussian War necessitated the withdrawal of the French troops from Rome, and immediately after that event the forces of King Victor Emmanuel appeared before Rome and occupied it to the great satisfaction of the Romans, and in spite of all the protests of the pope. The latter lost his temporal powers, although he was permitted to retain the Vatican. This completed the unification of Italy. The completion of the unification of Italy, of course, created many difficult internal problems, chief of which was the adjustment between the state and the church. The latter, as represented by the pope, refused to become reconciled to the new conditions or to acknowledge the legality of the so-called Laws of the Guarantees, according to which he was given all the privileges of a sovereign, the possession of the Vatican and Lateran palaces, and a considerable annual income. None of these appeased the church, which steadfastly refused to recognize the existence of the Italian state. The difficulties created thereby can readily be understood if one considers the immense influence that the Roman Catholic Church possesses over the minds of its members, and if one further remembers that practically all Italians are devout Catholics.