On Sept. 30, 2023, Pope Francis swore in 21 clergymen as new members of the College of Cardinals. The College is an important part of the church’s governance structure – each new member takes a formal oath during a ritual ceremony in the presence of present members of the College.

This assembly of cardinals, known as a consistory, is the ninth that Francis has held to create new cardinals since 2013, when he succeeded the retiring Pope Benedict XVI.

The new appointments will take the membership of the College from 221 to 242, including retirees. Francis has ensured that the College includes clergy from around the world and is representative of the diversity within Catholicism.

As a specialist in medieval Christianity, I have studied the complex history of the College of Cardinals. Shaped by past challenges, it is a crucial institution – for its members will elect the next pope and help develop the policies the Catholic Church will follow in the future.

During the Roman Empire, when Christianity was illegal, Christians would meet secretly. These meetings were often held in private homes called house churches – domestic buildings that were later adapted solely for worship by members of the local Christian community.

It was during this time that leadership of these communities developed into three main orders of ordained clergy: Overseers became bishop, elders became priests, and ministers became deacons.

After the legalization of Christianity in the early fourth century, Christians were free to build large, more elaborate public buildings for worship, which often expanded some of these original house churches. New churches were also built in various sections of Rome, as well as in seven areas surrounding the city — like suburbs – called the suburbicarian churches.

By the sixth century, key members of the clergy staffing many of these Roman and Italian churches, especially the older ones, were referred to as cardinals, from the Latin word referring to a hinge, or a central joint. Leading deacons, senior priests and prominent bishops serving these parishes were all called cardinals.

Over these later centuries, Christianity also spread more widely north of the Alps, and the numbers of Christian churches and clergy expanded. However, because of ongoing warfare, conquest and political turmoil, Christianity in western Europe entered a more turbulent period. Popes came to exert political as well as spiritual power, leaving the office of the papacy vulnerable to the influence of competing secular powers, as well as powerful local Roman families and foreign rulers.

This became such a problem that in 769, under Pope Stephen III, a council held at one of the central churches in Rome – St. John Lateran – ruled that no layperson could be elected pope or influence the election of anyone to the papacy; only candidates holding the title of cardinal could be elected pope.

...continued