Nepotism gained its name after the church practice in the Middle Ages, when some Catholic popes and bishops, who had taken vows of chastity, and therefore usually had no children of their own, gave their nephews such positions of preference as were often accorded by fathers to son.
Several popes elevated nephews and other relatives to the cardinalate. Often, such appointments were a means of continuing a papal "dynasty."
For instance, Pope Callixtus III, head of the Borgia family, made two of his nephews cardinals; one of them, Rodrigo, later used his position as a cardinal as a stepping stone to the papacy, becoming Pope Alexander VI...
Alexander then elevated Alessandro Farnese, his mistress's brother, to cardinal; Farnese would later go on to become Pope Paul III Paul also engaged in nepotism, appointing, for instance, two nephews, aged 14 and 16, as cardinals. The practice was finally ended when Pope Innocent XII issued the bull Romanum decet Pontificem
, in 1692. The papal bull prohibited popes in all times from bestowing estates, offices, or revenues on any relative, with the exception that one qualified relative (at most) could be made a cardinal.
Coincidentally, the Church of the East from the 16th to the 19th centuries made the Patriarch a hereditary title, being passed down from Patriarch-uncle to nephew; however, this move was initiated in the face of Timur's destruction of Nestorian Monasteries throughout Asia (monks being the key source of priests and patriarchs for the Church), in an attempt to guarantee the existence of a patriarch. This proved to be a catalyst for the schism that exists today between Chaldean Catholics and Assyrian "Nestorians