A dynasty is a sequence of rulers from the same family, usually in the context of a feudal or monarchical system, but sometimes also appearing in republics. Alternative terms for "dynasty" may include "house", "family" and "clan", among others. The longest surviving dynasty in the world is the Imperial House of Japan, otherwise known as the Yamato Dynasty, whose reign is traditionally dated to 660 BC and historically attested from 781 AD.
The dynastic family or lineage may be known as a "noble house", which may be styled as "imperial", "royal", "princely", "ducal", "comital", "baronial" etc., depending upon the chief or present title borne by its members.
Historians periodize the histories of many states and civilizations, such as Ancient Egypt (3100 – 30 BC) and Ancient and Imperial China (2070 BC – 1912 AD), using a framework of successive dynasties. As such, the term "dynasty" may be used to delimit the era during which a family reigned, and also to describe events, trends and artifacts of that period (e.g., "a Ming Dynasty vase"). The word "dynasty" itself is often dropped from such adjectival references (e.g., "a Ming vase").
Before the 20th century, dynasties throughout the world have traditionally been reckoned patrilineally, such as under the Frankish Salic law. In polities where it was permitted, succession through a daughter usually established a new dynasty in her husband's ruling house. This has changed in some places in Europe, where succession law and conventions have maintained dynasties de jure through a female. For instance, the House of Windsor will be maintained through the children of Queen Elizabeth II, as it did with the monarchy of the Netherlands, whose dynasty remained the House of Orange-Nassau through three successive Queens Regnant. The earliest such example among major European monarchies was in the Russian Empire in the 18th century, where the name of the House of Romanov was maintained through Grand Duchess Anna Petrovna. This also happened in the case of Queen Maria II of Portugal, who married Prince Ferdinand of Saxe-Coburg and Gotha-Koháry, but whose descendants remained members of the House of Braganza, per Portuguese law, in fact since the 1800s the only female monarch in europe who had children belonging to a different house was Queen Victoria In Limpopo Province of South Africa, Balobedu determined descent matrilineally, while rulers have at other times adopted the name of their mother's dynasty when coming into her inheritance. Less frequently, a monarchy has alternated or been rotated, in a multi-dynastic (or polydynastic) system—that is, the most senior living members of parallel dynasties, at any point in time, constitute the line of succession.
Not all feudal states or monarchies were or are ruled by dynasties; modern examples are the Vatican City State, the Principality of Andorra, and the Sovereign Military Hospitaller Order of Saint John of Jerusalem, of Rhodes and of Malta. Throughout history, there were monarchs that did not belong to any dynasty; non-dynastic rulers include King Arioald of the Lombards and Emperor Phocas of the Byzantine Empire. Dynasties ruling subnational monarchies do not possess sovereign rights; two modern examples are the monarchies of Malaysia and the royal families of the United Arab Emirates.
The word "dynasty" is sometimes used informally for people who are not rulers but are, for example, members of a family with influence and power in other areas, such as a series of successive owners of a major company. It is also extended to unrelated people, such as major poets of the same school or various rosters of a single sports team.