Prince Carlos of Bourbon-Two Sicilies

2.1. First Marriage

On 14 February 1901, in Madrid, Prince Carlos married Mercedes, Princess of Asturias. Mercedes was the elder daughter of the late King Alfonso XII of Spain and his wife, Archduchess Maria Christina of Austria. At the time of their marriage, Mercedes was the elder sister and heir presumptive to her unmarried teenage brother, King Alfonso XIII of Spain. A week before the wedding, on 7 February 1901, Carlos was formally granted the title of Infante of Spain, solidifying his position within the Spanish royal family.

Carlos and Mercedes had three children:

• Don Alfonso, Prince of the Two Sicilies, Infante of Spain (1901-1964), who later became the Duke of Calabria from 1960 to 1964.
• Don Fernando of Bourbon-Two Sicilies (1903-1905), who died in San Sebastián one year after his mother's death.
• Doña Isabella Alfonsa, Princess of the Two Sicilies, Infanta of Spain (1904-1985). She married Count Jan Kanty Zamoyski (1900-1961) and had issue.

Tragically, Mercedes died in childbirth in 1904, leaving Prince Carlos a widower.

2.2. Second Marriage

In 1907, Prince Carlos married for the second time to Princess Louise of Orléans, a daughter of Prince Philippe, Count of Paris, the Orleanist claimant to the French throne.

The couple had four children:

• Don Carlos of Bourbon-Two Sicilies (1908-1936), who was killed during the Spanish Civil War.
• Doña María de los Dolores of Bourbon-Two Sicilies (1909-1996). In 1937, she married Prince Augustyn Józef Czartoryski (1907-1946) and had one surviving son, Adam Karol Czartoryski. She later remarried to Carlos Chias in 1950.
• Doña María de las Mercedes of Bourbon-Two Sicilies (1910-2000), who married Infante Juan, Count of Barcelona, and became the mother of King Juan Carlos I of Spain.
• Doña María de la Esperanza of Bourbon-Two Sicilies (1914-2005), who married Prince Pedro Gastão of Orléans-Braganza, a claimant to the Brazilian imperial throne.

2.3. Descendants

Prince Carlos's extensive progeny ensured his lasting impact on European royalty. His descendants include prominent figures such as King Felipe VI of Spain, Infante Carlos, Duke of Calabria, Prince Pedro Carlos of Orléans-Braganza, and Prince Peter of Yugoslavia, among others, illustrating the wide reach of his family connections across various European dynasties.

4.1. Renunciation of Succession Rights

In 1894, Prince Carlos's father, Alfonso, became the head of the House of Bourbon-Two Sicilies. However, upon his first marriage to Mercedes, Princess of Asturias, Prince Carlos formally renounced his future rights of succession to the non-existent Crown of the Two Sicilies. This renunciation occurred on 14 December 1900, formalized in an official document known as the Act of Cannes. This act was stipulated by requirements outlined in the Treaty of Naples of 1759 and the Pragmatic Decree of 6 October 1759, which mandated that the Crown of Spain should not be combined with the "Italian Sovereignty" (referring to the Kingdom of the Two Sicilies). This renunciation was a crucial step in allowing him to become an Infante of Spain and marry into the Spanish royal family.

4.2. Succession Dispute

A significant controversy over the headship of the House of Bourbon-Two Sicilies arose following the death of Carlos's elder brother, Prince Ferdinand Pius, Duke of Calabria, in 1960, who died without male issue. This created a dispute between Carlos's son, Infante Alfonso, Duke of Calabria, and Carlos's younger brother, Prince Ranieri, Duke of Castro.

The competing claims were as follows:

• Alfonso's Claim:** Based on the law of primogeniture, Alfonso, as the eldest son of Prince Carlos, was considered the rightful heir. He argued that his father's renunciation in the Act of Cannes was only a conditional promise, valid only if the Crown of the Kingdom of the Two Sicilies were to be united with the Spanish Crown. Since this union never materialized, Alfonso asserted that the act had no effect, and therefore, he reclaimed his rights.
• Ranieri's Claim:** Ranieri contended that Prince Carlos had unequivocally renounced his rights and those of his descendants according to the Act of Cannes, thereby making Ranieri, as the next senior male line descendant not subject to such renunciation, the legitimate head of the house.

The dispute remains unresolved, with the descendants of both Alfonso and Ranieri continuing to assert their respective claims to the headship of the House of Bourbon-Two Sicilies. Alfonso's claim was recognized by the heads of various lines of the House of Bourbon, though not by the head of the Orléans family. In 1983, the Spanish Council of State, following investigations by the Ministries of Justice and Foreign Affairs, the Royal Academy of Jurisprudence and Legislation, and the Institute Salazar y Castro, unanimously concluded in favour of Infante Don Alfonso's only son, Prince and Infante Don Carlos. This position was also shared by the Spanish Royal House.