A dynasty is a line of rulers from the same family, usually in the context of a feudal or monarchical system but sometimes also appearing in elective republics. The dynastic family or lineage is known as a house; this may be styled "royal", "princely", "comital", etc. depending upon the chief or present title borne by its members. The names of the dynasty and the house are not always identical: the Han dynasty of Chinese history, for example, was ruled by the Liu family. Historians consider many sovereign states' histories—particularly Ancient Egypt and Imperial China—within a framework of successive dynasties. As such, the term "dynasty" may be used to delimit the era during which the family reigned and to describe the events, trends, and artifacts of that period ("a Ming-dynasty vase"). The word "dynasty" itself is often dropped from such adjectival references ("a Ming vase").Until the 19th and 20th century, it was taken for granted that a legitimate function of a monarch was to aggrandize his dynasty: that is, to increase the territory, wealth, and power of his family members. The longest-surviving dynasty in the world is the Imperial House of Japan, the Yamato dynasty, which is traditionally dated to 660 BC and has lasted until the present day.Dynasties throughout the world have traditionally been reckoned patrilineally, most famously under the Frankish Salic law, with succession through a daughter (when permitted) considered to establish a new dynasty in her husband's house. However, some states in North American and Africa, such as Christian Nubia, determined descent matrilineally, while male rulers have at other times adopted the name of their wife or mother's dynasty when coming into their inheritance: examples include the Dutch House of Orange, the Georgian Bagrationi, and Habsburg-Lorraine.The word "dynasty" is sometimes used informally for people who are not rulers but, 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. A long-running television series about such a family was produced with the name Dynasty.