Ferdinand I of the Two Sicilies in the context of "House of Bourbon-Two Sicilies"

The Viceroys of Sicily (Italian: Viceré di Sicilia) were the regents of the government of the Kingdom of Sicily in place of the Spanish Kings who acquired the title of King of Sicily from 1412 to 1759. In 1806 Ferdinand I of the Two Sicilies, having established himself on the island, abolished the office and established in its place those of lieutenant and captain general.

The Kingdom of Naples (Italian: Regno di Napoli; Neapolitan: Regno 'e Napule) was a French client state in southern Italy that existed from 1806 to 1815. It was founded after the Bourbon Ferdinand IV & III of Naples and Sicily sided with the Third Coalition against Napoleon, and was in return ousted from his kingdom by a French invasion. Joseph Bonaparte, elder brother of Napoleon, was installed in his stead: Joseph conferred the title "Prince of Naples" to be hereditary on his children and grandchildren. When Joseph became king of Spain in 1808, Napoleon appointed his brother-in-law Marshal Joachim Murat to take his place. Murat was later deposed by the Congress of Vienna in 1815 after striking at Austria in the Neapolitan War, in which he was decisively defeated at the Battle of Tolentino.

Maria Theresa of Naples and Sicily (6 June 1772 – 13 April 1807) was the first Empress of Austria and last Holy Roman Empress as the spouse of Francis II. She was born a Princess of Naples as the eldest daughter of King Ferdinand I of the Two Sicilies and Queen Maria Carolina.

James I the Conqueror (Catalan: Jaume I or Jaume el Conqueridor; Aragonese: Chaime I o Conqueridor; 2 February 1208 – 27 July 1276) was King of Aragon, Count of Barcelona, and Lord of Montpellier from 1213 to 1276; King of Majorca from 1231 to 1276; and King of Valencia from 1238 to 1276. His long reign of 62 years is not only the longest of any Iberian monarch, but one of the longest monarchical reigns in history, ahead of Hirohito but remaining behind Queen Elizabeth II, Queen Victoria, and Ferdinand I of the Two Sicilies and King Louis XIV

King James I saw the expansion of the Crown of Aragon in three directions: Languedoc to the north, the Balearic Islands to the southeast, and Valencia to the south. By a treaty with Louis IX of France, he achieved the renunciation of any possible claim of French suzerainty over the County of Barcelona and the other Catalan counties, while he renounced northward expansion and taking back the once Catalan territories in Occitania and vassal counties loyal to the County of Barcelona, lands that were lost by his father Peter II of Aragon in the Battle of Muret during the Albigensian Crusade and annexed by the Kingdom of France, and then decided to turn south. His great part in the Reconquista was similar in Mediterranean Spain to that of his contemporary Ferdinand III of Castile in Andalusia. One of the main reasons for this formal renunciation of most of the once Catalan territories in Languedoc and Occitania, and any expansion into them, is that he was raised by the Knights Templar Crusaders, who had defeated his father, who was fighting for the Pope alongside the French. It was thus effectively forbidden for him to try to maintain the traditional influence of the Count of Barcelona that previously existed in Occitania and Languedoc.

The Neapolitan War, also known as the Austro-Neapolitan War, was a conflict between the Napoleonic Kingdom of Naples and the Austrian Empire. It started on 15 March 1815, when King Joachim Murat declared war on Austria, and ended on 20 May 1815, with the signing of the Treaty of Casalanza. The war occurred during the Hundred Days between Napoleon's return from exile and before he left Paris to be decisively defeated at the Battle of Waterloo. The war was triggered by a pro-Napoleon uprising in Naples and ended with a decisive Austrian victory at the Battle of Tolentino, after which Bourbon monarch Ferdinand IV was reinstated as King of Naples and Sicily. However, the intervention by Austria caused resentment in Italy, which further spurred on the drive towards Italian unification.

The invasion of Naples was a military campaign of the War of the Third Coalition in 1806. It began when a French army led by Marshal André Masséna marched from Northern Italy into the Kingdom of Naples, an ally of the Coalition against France ruled by King Ferdinand IV. The Neapolitan army was defeated at Campo Tenese and rapidly disintegrated. The invasion was eventually successful despite some setbacks, including the prolonged Siege of Gaeta, the British victory at Maida, and a stubborn guerrilla war by local peasants against the French. Total success eluded the French because Ferdinand withdrew to his domain in Sicily, where he was protected by the Royal Navy and a British Army garrison. In 1806, Emperor Napoleon appointed his brother Joseph Bonaparte to reign over the newly formed Napoleonic kingdom of Naples in Southern Italy.

The proximate cause of the invasion was Ferdinand's double-crossing of Napoleon. Wanting to keep things quiet in southern Italy, Napoleon and Ferdinand signed a convention that specified that the French would evacuate Apulia. In return, the Kingdom of Naples would stay neutral in the impending War of the Third Coalition. When the French occupying force marched away, Ferdinand admitted British and Russian armies into his kingdom. In December 1805, Napoleon's armies crushed the armies of Austria and Russia. When the Russian force in Naples was recalled, the British expedition withdrew, exposing Ferdinand's kingdom to French retribution.

The Battle of Tolentino was fought from 2–3 May 1815 near Tolentino, Kingdom of Naples in what is now Marche, Italy: it was the decisive battle in the Neapolitan War, fought by the Napoleonic King of Naples Joachim Murat to keep the throne after the Congress of Vienna. The battle occurred during the Hundred Days following Napoleon's return from exile and, like the Battle of Waterloo, resulted in a decisive victory for the Seventh Coalition, leading to the restoration of the previous Bourbon king, Ferdinand I.

The Parthenopean Republic (Italian: Repubblica Partenopea, French: République Parthénopéenne) or Neapolitan Republic (Italian: Repubblica Napoletana) was a short-lived sister republic in Southern Italy established during the French Revolutionary Wars following the defeat of the armies of Ferdinand IV. The republic existed from 21 January to 13 June 1799, collapsing when the Sanfedists returned Ferdinand to power, after which he harshly subdued republican activities.