The Hundred Thousand Sons of Saint Louis (7 April-7 November 1823), also known as the Spanish Expedition, was the popular name for the French invasion of Spain in 1823, referencing the 95,000 French troops who had been sent to restore Fernando VII of Spain's powers. The invasion was caused by the start of the Trienio Liberal liberal regime in 1820, which began when Rafael del Riego and Francisco Ballesteros led a military coup against the monarchy and forced Fernando to reinstate the Constitution of 1812. The French met with the other members of the Quintuple Alliance in the Congress of Verona to discuss the situation in Spain, and King Louis XVIII of France was permitted to send four French corps to invade Spain and restore the Bourbon absolute monarchy. The French armies rained down through northern Spain, with the provisional Spanish capital of Cadiz being their strategic objective. The French forces managed to capture all of northern Spain in just a few months, and Cadiz's fall on 30 September 1823 allowed for the French to restore Fernando VII as the absolute ruler of Spain. The leaders of the liberal Trienio were forced into exile or executed, and Spain would return to being an absolute monarchy; discontent with Fernando's rule would simmer during the ensuing "Ominous Decade".
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