Spain experienced a revolution in 1820, in which the liberals gained power and reestablished a constitution promulgated in 1812. This event had notable repercussions in Italy. In the Kingdom of the Two Sicilies, former members of Murat's army, affiliated with the Carbonari, marched on Naples (July 2, 1820) to the cry of "Long live liberty and the constitution." They found support in the army and among the bourgeoisie. King Ferdinand was forced to yield to demands for the introduction of the Spanish constitution, which limited royal powers, decreased centralization, and reduced the influence of the capital. The new regime proved short-lived, however, for it had too many enemies. The king sought to recover his former powers; and Sicilian dissidents attempted to reestablish their island's separate status, though their movement was brutally suppressed by the Neapolitan constitutional government, assisted by Austria. At the Congress of Vienna, Austria had been conceded the prerogative of intervening, if necessary, to maintain the restored Bourbon monarchy. Thus, in January 1821 Metternich convened an international congress at Laibach (Ljubljana) attended by representatives of the European powers and of the Italian states and by King Ferdinand himself. Overcoming weak Anglo-French opposition, Ferdinand obtained approval for military intervention. Accordingly, the Austrian army entered the kingdom and occupied Naples on March 23, 1821, reestablishing the king's absolute government.
Congress of Laibach (Jan. 26-May 12, 1821), meeting of the Holy Alliance powers (all European rulers except those of Britain, the Ottoman Empire, and the papacy) at Laibach (now Ljubljana, Slovenia) that set the conditions for Austrian intervention in and occupation of the Two Sicilies in action against the Neapolitan revolution (July 1820). As such, it was a triumph for antiliberal Austrian policy, and also, because of British and French dissension, it was a demonstration of the decline of the congress system.
Attended by the monarchs of Russia, Austria, and Prussia and their chief ministers, the kings of the Two Sicilies and Sardinia-Piedmont, the dukes of Modena and Tuscany, and British and French observers, the congress proclaimed its hostility to revolutionary regimes, agreed to abolish the Neapolitan constitution, and authorized the Austrian army to restore the absolutist monarchy. The British and French protested the decision, thereby encouraging unsuccessful resistance among the Neapolitans. A similar revolt in Piedmont was put down by the Austrians at Novara on April 8, 1821.