About Infante Carlos, Duke of Calabria
Don Carlos María Alfonso Marcelo de Borbón-Dos Sicilias y Borbón-Parma, Infante of Spain, Duke of Calabria (16 January 1938 – 5 October 2015) was, at his death, the last male infante of Spain during the reigns of his cousins King Juan Carlos I and King Felipe VI. Additionally, he was also one of two claimants to the headship of the dynasty which ruled the Kingdom of the Two Sicilies prior to its incorporation into the Kingdom of Italy in 1861, in which capacity he was also the Grand Master of one of the three branches of the Sacred Military Constantinian Order of Saint George. Carlos's father, Infante Alfonso, had asserted himself as rightful heir because his late father, Carlo of Bourbon-Two Sicilies (1870–1949), had been Ferdinand's next oldest brother. Prince Carlos was created an Infante of Spain by King Juan Carlos I of Spain by Royal Decree 2412 dated 16 December 1994 as the "representative of a line linked historically to the Spanish Crown". Raised from infancy side-by-side with his future king, Juan Carlos I (Carlos's elder by 11 days), the cousins attended school together first in Switzerland and later in Spain.
Biography source: Wikipedia. The profile adds birthday-specific historical context from the Celebs Birthday Today editorial database.