The Battle of Trocadero August 31, 1823, established the victory of the Ultra-Catholic reaction to the right in the post-Napoleonic period.

Prelude

The European powers monitored three years of factional struggles in Spain, where Ferdinand VII refused to restore the liberal Spanish Constitution of 1812 and had faced a revolution since 1820, led by the constitutionalist and patriot Rafael del Riego y Nuñez (1785-1823). An international meeting was called, the Congress of Verona, which met in Austrian-controlled territory in Italy in October of 1822. The ministers' monarchic governments were alarmed by the capture of Ferdinand VII of Spain by armed revolutionary liberals opposed to absolutism, who sought a constitutional monarchy for Spain by restoring the abrogated Constitution of 1812.

The Congress — with Britain pointedly abstaining — authorized France to intervene in the conflict and restore Ferdinand to his throne. The only objection to the plan was raised by Britain.
On April 17, 1823, French forces led by Charles X's son, Louis-Antoine, Duke of Angoulême (1775-1844), crossed the Pyrenees into Spain, welcomed by the Basques and in Catalonia. The duke dispatched a force to besiege San Sebastian while he launched an attack on Madrid, held by the revolutionaries. On May 23, the rebel government withdrew from Madrid to Seville, Madrid's military commander secretly capitulated and fled to France, and the leaderless Madrid garrison could not keep out the French, who seized the city and installed a regent selected by conservative royalists, pending Ferdinand's expected return.

The French moved south to besiege the revolutionaries under Colonel Riego at Cádiz, where the Cortes (national legislature) had taken Ferdinand.

The Battle

Riego's forces suffered defeat at the fort of Trocadero on August 31, 1823, and when Cádiz fell to the French on September 23, 1823, Ferdinand was handed over to them and restored to the throne.

Among those fighting with the French was Carlo Alberto, Prince of Carignano, soon to be King of Sardinia.

Aftermath

Renouncing his prior promise of amnesty for the revolutionaries, the king ordered ruthless measures of reprisal against them while French troops stood by. The proclamation of the "Monroe Doctrine" against the intervention of European nations in America, on December 2, was partly affected by these developments in Spain.

The fall of Trocadero was considered worth commemorating in Paris, with the Place de Trocadéro, where the city was expanding to the edges of the Bois de Boulogne.

Victor Hugo on the Battle of Trocadero

Victor Hugo in Les Misérables (Volume II, Book 2, chapter 3) thought otherwise. Looking back from the vantage of 1862, he spoke for the progressive liberals of his generation when he devoted a long aside on the ambiguous meanings of Trocadero for France, the "hideous contradiction":

A grand family affair for the house of Bourbon; the branch of France succoring and protecting the branch of Madrid... the sansculottes resuscitated, to the great terror of dowagers, under the name of descamisados; monarchy opposing an obstacle to progress described as anarchy; the theories of '89 roughly interrupted in the sap; a European halt called to the French idea, which was making the tour of the world; beside the son of France as generalissimo, the Prince de Carignan, afterwards Charles Albert, enrolling himself in that crusade of kings against people as a volunteer... the soldiers of the Empire setting out on a fresh campaign, but aged, saddened, after eight years of repose, and under the white cockade... monks mingled with our troops; the spirit of liberty and of novelty brought to its senses by bayonets; principles slaughtered by cannonades; France undoing by her arms that which she had done by her mind... but little bloodshed, little honor won, shame for some, glory for no one. Such was this war, made by the princes descended from Louis XIV, and conducted by generals who had been under Napoleon. Its sad fate was to recall neither the grand war nor grand politics.
Some feats of arms were serious; the taking of the Trocadero, among others, was a fine military action; but after all, we repeat, the trumpets of this war give back a cracked sound, the whole effect was suspicious; history approves of France for making a difficulty about accepting this false triumph. It seemed evident that certain Spanish officers charged with resistance yielded too easily; the idea of corruption was connected with the victory; it appears as though generals and not battles had been won, and the conquering soldier returned humiliated. A debasing war, in short, in which the Bank of France could be read in the folds of the flag.
In that campaign, the object of the French soldier, the son of democracy, was the conquest of a yoke for others. .. an outrage on the generous Spanish nation, was then, at the same time, an outrage on the French Revolution.
As for the Bourbons, the war of 1823 was fatal to them. They took it for a success. They did not perceive the danger that lies in having an idea slain to order. They went astray, in their innocence, to such a degree that they introduced the immense enfeeblement of a crime into their establishment as an element of strength. The spirit of the ambush entered into their politics. 1830 had its germ in 1823. The Spanish campaign became in their counsels an argument for force and for adventures by right Divine. France, having re-established el rey netto in Spain, might well have re-established the absolute king at home. They fell into the alarming error of taking the obedience of the soldier for the consent of the nation. Such confidence is the ruin of thrones. It is not permitted to fall asleep, either in the shadow of a machineel tree, nor in the shadow of an army.