The concept of cardinal-nephews is tied to the practice of nepotism within the Catholic Church, particularly during the Middle Ages and reaffirmed throughout the Renaissance. Cardinal-nephews were cardinals appointed by a pope who was also their relative, a practice that rose to prominence between the 16th and 17th centuries. This period marks the height of such appointments, where the act of elevating a family member to cardinal status became increasingly normalized within the hierarchical structure of the church. Notably, the last instance of a cardinal-nephew being named occurred in 1689, with the subsequent abolition of the practice taking place in 1692 by Pope Innocent XII through an anti-nepotism bull known as Romanum decet pontificem.
The origin of the term 'nepotism' itself finds its roots in this practice, emerging in the English language around 1669, specifically denoting the preferential treatment of relatives in appointive roles, especially within ecclesiastical contexts. Throughout much of the Avignon Papacy, a period from 1309 to 1377 when the papal residence was located in Avignon rather than Rome, having a cardinal-nephew became a common and widely accepted practice. Indeed, it became a notable trend among Renaissance popes, as every one of them who appointed cardinals tended to favor relatives, with the role of nephew being particularly prevalent. Interestingly, there were exceptions to this trend, such as Pope Alexander VI, who elevated his own son instead of a nephew, highlighting the blurred lines of nepotism in papal appointments.
This reshaping of cardinal appointments shed light on the intertwining of familial loyalty and governance within the church, underscoring the broader dynamics at play in ecclesiastical authority during that era. The moves made by various popes to appoint relatives contributed to the perception of the church as an institution heavily influenced by familial connections, leading to calls for reforms. The eventual ban on the practice indicated a shift towards a more merit-based method of appointment within the college of cardinals, striving to alleviate the concerns surrounding the integrity of the papacy at that time.