Mariano

One of stories about Mariano is that for a little while he was “hostage” for the good keeping of Prince Victor Emanuel afterwards King of a United Italy. He had to sleep, eat, work, play with him day and night, accompanying him even on royal visits to King Ferdinand and Ildefonso or Aranjuez.

To add to your Spanish History:

In 1820 a liberal revolution initiated by junior army officers (unwilling to be sent to South America in a fruitless attempt to support royal interests against the majority wishes for independence) aimed to force a reluctant Ferdinand VII to adopt the Constitution of 1812 a form of Constitutional Government. Civil support came from members of the Freemasonry movement which opposed royal and church power. Parts of Spain were close to anarchy. In many towns there were local militias. In July 1822 there was a brawl between the army and the militia of Madrid initiated by the Guards regiment (the best trained and most loyal part of the army). The Cortes – the Spanish Parliament – wanted Ferdinand to rebuke the regiment and put pressure on him and his Ministers. The Guards promptly attacked the Madrid militia but were beaten. As a result the King had to accept a much more radical Ministry, and the amount of anarchy further increased. However the allied powers (Great Britain abstained) fearing further revolution in Europe asked Louis XVIII of France to intervene. In April 1823 he sent the Duc d'Angoulême at the head of a large army into Spain to release Ferdinand from his radical ministers. The Battle of Trocadero was decisive.

Wikipedia: The Battle of Trocadero August 31st 1823, established the victory of the Ultra-Catholic reaction to the right in the post-Napoleonic period. 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 Nunez (1785-1823). An international meeting was called, the Congress of Verona, which met in Austrian-controlled territory in Italy in October 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 the future Charles X's son, Louis-Antoine, Duke of Angouleme (1775-1844), crossed the Pyrennees into Spain, welcomed by the Basques and Catalonians. 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 Cadiz, where the Cortes (national legislature) had taken Ferdinand. Riego's forces suffered defeat at the fort of Trocadero on August 31, 1823, and when Cadiz 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.

Carlo Alberto (b. Oct. 2, 1798, Turin, Piedmont, French Republic--d. July 28, 1849, Oporto, Port.) was the father of Victor Emmanuel II. He was king of Sardinia-Piedmont (1831-49) during the turbulent period of the Risorgimento, the movement for the unification of Italy. His political vacillations make him an enigmatic personality.

Victor Emmanuel II (March 14 1820-January 9 1878) was the King of Piedmont, Savoy and Sardinia from 1849-1861. On February 18 1861, he assumed the title King of Italy to become the first king of a united Italy.

Victor Hugo in Les Miserables (Volume II, Book 2, chapter 3) wrote 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 succouring 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 Carlo Alberto, 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 honour 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.