Cadet (genealogy) in the context of "Substantive title"

A cadet branch consists of the male-line descendants of a monarch's, ruler's or patriarch's younger sons (cadets). In the ruling dynasties and noble families of much of Europe and Asia, the family's major assets (realm, titles, fiefs, properties, lands and income) have historically been passed from the father to his firstborn son in what is known as primogeniture; younger sons, the cadets, generally inherited less wealth and authority (such as a small appanage) to pass on to future generations of their descendants.

In families and cultures in which that was not the custom or law, such as the feudal Holy Roman Empire, the equal distribution of the family's holdings among male members was eventually apt to so fragment the inheritance as to render it too small to sustain the descendants at the socio-economic level of their forefather—and indeed, too small to efficiently manage or effectively defend. Moreover, brothers and their descendants sometimes quarreled over their allocations, or even became estranged. While agnatic primogeniture became a common way of keeping the family's wealth intact and reducing familial disputes, it did so at the expense of younger sons and their descendants. Both before and after a state legal default of inheritance by primogeniture, younger brothers sometimes vied with older brothers to be chosen as their father's heir or, after the choice was made, sought to usurp the elder's birthright.

The Principality of Reuss-Gera (German: Fürstentum Reuß-Gera), officially called the Principality of Reuss Junior Line (German: Fürstentum Reuß jüngerer Linie) after 1848, was a sovereign state in modern Germany, ruled by members of the House of Reuss. It was one of the successor states of the Imperial County of Reuss. The Counts Reuss, with their respective capitals and Residenzen at Gera, Schleiz, Lobenstein, Köstritz and Ebersdorf, were all elevated to the title of prince (Fürst) in 1806. Their successor branch heads shared that title, while their cadets were also each titled prince (Prinz). Thus all males of the family were properly "Prince Heinrich (Roman numeral) Reuss, J.L.", without use of a nobiliary particle, although for convenience their branch names remained in colloquial use (for example, "Prince Heinrich I Reuss of Köstritz").

Angoulême (L'Angoumois) in western France was part of the Carolingian Kingdom of Aquitaine. Under Charlemagne's successors, the local count of Angoulême was independent and the county was not united with the French crown until 1308. By the terms of the Treaty of Brétigny (1360) the Angoumois, then ruled by the counts of Angoulême, was ceded to King Edward III of England. In 1371 it became a fief of Duke John of Berry and then passed to Duke Louis I of Orleans, both of whom were cadets of the French royal family. From then on it was held by cadets of the Valois House of Orleans, until Francis of Angoulême, became king of France in 1515. Angoumois was definitively incorporated into the French crown lands, as a duchy.

Grand Duke George Mikhailovich of Russia (Russian: Георгий Михайлович Романов, romanized: Gěorgij Mihajlovič Romanov, also spelled Romanoff; German: Georg Michailowitsch Romanow; born 13 March 1981) is the heir apparent to Maria Vladimirovna, a claimant to the disputed Headship of the Imperial Family of Russia. He is the only child of Maria and her former husband, Prince Franz Wilhelm of Prussia. George's mother attributes to him the title of Tsesarevich and he bears the prefix of "Grand Duke" with the style of Imperial Highness which is still being questioned. As the son of a cadet member of the branch of the House of Hohenzollern which formerly ruled the German Empire and Kingdom of Prussia, he is also sometimes entitled "Prince of Prussia" with the style of Royal Highness.

Francisco Fernández de la Cueva y Fernández de la Cueva, (Genoa, Italy, 17 November 1666 – Madrid, Spain, 28 June 1724) was the 10th Duke of Alburquerque, a Grandee of Spain, a Knight of the Order of the Golden Fleece from 1707, and Viceroy of New Spain from 27 November 1702 to 13 November 1710. He was viceroy during the War of Spanish Succession and his tenure as Viceroy of New Spain is commemorated in the namesake of Albuquerque, New Mexico.

He was the nephew of Francisco IV Fernández de la Cueva – Colonna, (* Barcelona, 1618/1619 – † Madrid (Palacio Real) 27 March 1676), 8th Duque de Alburquerque and many other lesser titles, also a Viceroy of New Spain, (1653–1660), and Viceroy of Sicily, (1667–1670), and the son of the 9th Duke of Alburquerque, and many other lesser titles, the cadet brother of the 8th Duke, and inheritor of the titles, Melchor Fernández de la Cueva (es; fr; it) (* Madrid, 2 March 1625 – † Madrid 12 October 1686).