Royal house

A royal house or royal dynasty is a familial designation, or family name of sorts, used by royalty. It generally represents the members of a family in various senior and junior or cadet branches, who are loosely related but not necessarily of the same immediate kin. Unlike most westerners, many of the world's royal families do not have family names, and those that have adopted them rarely use them. They are referred to instead by their titles, often related to an area ruled or once ruled by that family. The name of a Royal House is not a surname; it is just a convenient way of dynastic identification of individuals.

Because of royal intermarriage and the creation of cadet branches, a royal house generally will not entirely correspond to one immediate family or place; members of the same house in different branches may rule entirely different countries and only be vaguely related; the family may have originated entirely elsewhere. The Capetian dynasty (that includes any direct descendant of Hugh Capet of France) is the oldest continuously ruling monarchial dynasty in Europe – it originates in 987 and is the current ruling house of Spain and Luxembourg.

The House of Wettin, as another example, originated in Germany as a comital family. Today, it no longer holds any status in Germany, but different branches sit on various thrones, including those of the United Kingdom, and Belgium. Former monarchs and consorts of Portugal, Bulgaria, and Mexico also belonged to this house, although they were not especially closely related to the aforementioned lines, as they descended from different branches, some of them distinct for many generations.

Royal house names in Europe were generally taken from the father; in cases where a Queen regnant married a prince of another house, their children (and therefore subsequent monarchs) belonged to the house of the prince. Thus Queen Victoria belonged to the House of Hanover, but her male-line descendants belong to the house of her husband Albert, which is Saxe-Coburg and Gotha, a branch of the House of Wettin. The name was changed to Windsor in 1917.

Nevertheless, this rule had several exceptions in other countries: After the marriage of Empress Maria Theresia of the House of Habsburg in the 18th century to a Lorraine prince, her issue took the name Habsburg-Lorraine in order to closely associate themselves with the previous Habsburg dynasty. After 1834, in Portugal, the issue of Queen Maria II of Portugal and Prince Consort Ferdinand of Saxe-Coburg-Gotha (styled King Consort Ferdinand II after the birth of his first child to the Queen) remained solely Bragança, in the family and the dynasty unchanged name, following Portuguese matriarchal celtic traditions.

More recently, in the 20th century, the children of Queens regnant in the Netherlands and Luxembourg have retained their maternal house association, and in the United Kingdom, Queen Elizabeth II's descendants by her husband, Prince Philip of Greece and Denmark, will remain Windsor, although they are patrilineally of Prince Phillip's House of Schleswig-Holstein-Sonderburg-Glücksburg, which, in turn, is a line of the House of Oldenburg. The House of Schleswig-Holstein-Sonderburg-Glücksburg rules in Norway and ruled in Greece, because the modern founding monarchs of those nations were initially princes invited from Denmark, which kingdom's royal house is a cadet branch of that house.

Another way in which the royal house of a given country may change is when a foreign prince is invited to fill a vacant throne or a next-of-kin from a foreign house succeeds. This occurred with the death of childless Queen Anne of the House of Stuart: she was succeeded by a prince of the House of Hanover who was her nearest Protestant relative.

Due to the dissolution of the British Empire into independent nations, the House of Windsor has ruled over 32 countries; 16 remain with the shared monarchy (known as the Commonwealth Realms), while the others have become republics.

Reigning sovereign Houses

Deposed or extinct sovereign Houses

The majority of these nations are now republics or part of republics. The Princely Houses of Germany often have given their own names to the states they ruled.