For his great services in establishing a firm government Marshal Soult was made prime minister, with De Broglie, Guizot, and Thiers among his associates. The chief event which marked his administration was a war with Holland, followed by the celebrated siege of Antwerp, which the Hollanders occupied with a large body of troops. England joined with France in this contest, which threatened to bring on a general European war; but the successful capture of the citadel of Antwerp, after a gallant defence, prevented that catastrophe. This successful siege vastly increased the military prestige of France, and brought Belgium completely under French influence. The remaining events which marked the ministry of Marshal Soult were the project of fortifying Paris by a series of detached forts of great strength, entirely surrounding the city, the liberal expenditure of money for public improvements, and the maintenance of the colony of Algeria. The first measure was postponed on account of the violent opposition of the Republicans, and the second was carried out with popular favor through the influence of Thiers. The Arc de l'Étoile was finished at an expense of two million francs; the Church of the Madeleine, at a cost of nearly three millions; the Panthéon, of 1,400,000; the Museum of Natural History, for which 2,400,000 francs were appropriated; the Church of St. Denis, 1,350,000; the École des Beaux Arts, 1,900,000; the Hotel du Quay d'Orsay, 3,450,000; besides other improvements, the chief of which was in canals, for which forty-four millions of francs were appropriated,--altogether nearly one hundred millions of francs, which of course furnished employment for discontented laborers. The retention of the Colony of Algeria resulted in improving the military strength of France, especially by the institution of the corps of Zouaves, which afterward furnished effective soldiers. It was in Africa that the ablest generals of Louis Napoleon were trained for the Crimean War. In 1834 Marshal Soult retired from the ministry, and a series of prime ministers rapidly succeeded one another, some of whom were able and of high character, but no one of whom made any great historical mark, until Thiers took the helm of government in 1836,--not like a modern English prime minister, who is supreme so long as he is supported by Parliament, but rather as the servant of the king, like the ministers of George III.