Hundred Thousand Sons of Saint Louis  The Hundred Thousand Sons of Saint Louis was the popular name for a French army mobilized in 1823 by the Bourbon King of France, Louis XVIII, to help the Spanish Royalists restore King Ferdinand VII of Spain to the absolute power of which he had been deprived during the Liberal Triennium. Despite the name, the actual number of troops was around 60,000. The force comprised some five army corps (the bulk of the French regular army) and was led by the Duke of Angoulême, the son of the future King Charles X of France. The French name of the conflict is "l'Expédition d'Espagne" ("the Expedition of Spain"). In 1822, Ferdinand VII applied the terms of the Congress of Vienna, lobbied for the assistance of the other absolute monarchs of Europe, in the process joining the Holy Alliance formed by Russia, Prussia, Austria and France to restore absolutism. In France, the ultra-royalists pressured Louis XVIII to intervene. To temper their counter-revolutionary ardor, the Duc de Richelieu deployed troops along the Pyrenees Mountains along the France-Spain border, charging them with halting the spread of Spanish liberalism and the "yellow fever" from encroaching into France. In September 1822 this ""cordon sanitaire"" became an observation corps and then very quickly transformed itself into a military expedition. The Holy Alliance (Russia, Austria and Prussia) refused Ferdinand's request for help, but the Quintuple Alliance (Russia, Britain, France, Prussia and Austria) at the Congress of Verona in October 1822 gave France a mandate to intervene and restore the Spanish monarchy. On 22 January 1823, a secret treaty was signed at the congress of Verona, allowing France to invade Spain to restore Ferdinand VII as an absolute monarch. With the agreement from the Holy Alliance, on 28 January 1823 Louis XVIII announced that "a hundred thousand Frenchmen are ready to march, invoking the name of Saint Louis, to safeguard the throne of Spain for a grandson of Henry IV of France". At the end of February, France's Chambres voted an extraordinary grant for the expedition. Chateaubriand and the ultra-royalists rejoiced; the royal army was going to prove its bravery and devotion in the face of Spanish liberals, fighting for the glory of the Bourbon monarchy. The new prime minister, Joseph de Villèle, intended to oppose the war.