The congress of Vienna had fostered the return to the pre-existing political situation before the Empire of Napoleon. This meant for Rome the restoration of the papal supremacy. In 1815 Pius VII returned to Rome and restored, together with the works of art that had been removed by the emperor, his temporal power over the city. From this date Rome became papal again, but this situation was not to last still long. In fact, the occupation of Napoleon had stimulated and provoked the rebirth of an Italian patriotism that eventually led to a series of nationalist reactions ended in 1861 with the complete unification of Italy under the house of Savoy. The city of Rome took an active part in the agitated period of the Risorgimento, the political renaissance of Italy, and shared with the rest of Europe the revolutionary ideals of liberty and independence. Under the guidance of Giuseppe Mazzini, an elected assembly proclaimed a republic in Rome, while the pope fled to Gaeta. When the French sent an army in support of the pope, in 1849, the defense of the city was entrusted to Guseppe Garibaldi, who made a heroic stand against the foreigners on the Janiculum Hill. In 1867, he tried again to rouse the romans against the papal government with the help of the Cairoli brothers, killed in the same year. The French garrison who had occupied Castel Sant'Angelo since 1849, escaped the city in 1849, fostering the entrance of the Italian army, leaded by Cadorna, through the breach in one of the Roman walls, Porta Pia. The papal headquarters in Rome were taken with the force by the kingdom of Italy in 1870 and the pope declared himself as "prisoner of the Vatican". This happening marked the end of the papal rule of the city and Rome, still contained within the Aurelian Walls, was proclaimed the capital of the united Italy in 1871.