Why Are Cardinals Called Cardinals?
Catholic cardinals — the clerics who assist and advise the pope — are not named after the red birds, as some imagine. Indeed, the common cardinal was not named until the 18th century, more than 1,000 years after the Church began calling its high-ranking officials “cardinals.” The birds, in fact, are named after the clerics.
The word “cardinal” comes from the Latin cardo, which means “hinge.”1 We might think here of the “cardinal virtues” — prudence, justice, fortitude, and temperance — which are so named because the other virtues hinge upon them (so to speak).
In the ecclesiastical world, the word cardo was originally applied to priests and bishops who had begun ministering in dioceses different from the ones in which they were ordained. In fact, we still say that Father So-and-So was incardinated into (or hinged onto) such-and-such diocese when he moves from one to another.
But how did the pope’s advisors come to be called cardinals or hinges?
The city of Rome contains within it six very ancient dioceses known as the “suburbicarian sees.”2 Sometime in the early Middle Ages (it’s unclear when), the popes began appointing only their most trusted advisors as bishops of these dioceses. Doing so, though, meant these bishops needed to be incardinated into or hinged onto those dioceses, since they were typically already priests or bishops elsewhere. “A person so incardinated,” one writer explains, “was a ‘cardinalis”” — a “cardinal”.3
Throughout the Middle Ages, the process of incardinating priests and bishops was common outside of Rome as well, and these men were also sometimes called “cardinals.” But the rising importance of these Roman suburbicarian clerics — these “Cardinal Bishops,” as they are still called — marks the likely beginning of the modern Catholic cardinal.
As time went on, the role grew in importance and the word cardinal, or hinge, took on a theological significance. There are a few explanations to that end.
A first explanation was offered by Glenn D. Kittler (d. 1986), a Catholic journalist from the middle of the last century. Kittler writes that, in the Middle Ages,
“The Christian community found itself relying increasingly on a group of men who knew their way around Rome, who knew which Romans would help them and which would not, which could be trusted and which could not. Their ability to open and close influential or threatening doors gave rise to a nickname: they were called hinge-men. The Roman word for ‘hinge’ was cardo.”4
Kittler’s account — that cardinals are “hinges” because they know how to turn the hinges of the right doors — is still sometimes proposed, but most historians are unconvinced. The story has been described as “a highly fanciful, not to say romantic, account.”5
A second explanation can be gleaned from the 11th century writings of Pope Leo IX (d. 1054). In the heat of the discussions that eventually resulted in the Great Schism, Leo IX wrote to the Patriarch of Constantinople insisting that the Roman papacy was the “hinge” upon which the entire Church turned. In that context, he remarked that his advisors, because their office participates in or hinges upon his own, are rightly called “cardinals.”
Leo IX’s thinking has become somewhat mainstream. Indeed, the theological significance of the word “cardinal” is now usually tied to the way these clerics participate in the work of the papacy — the larger hinge upon which the Church turns.6
See Anthony Lo Bello, Origins of Catholic Words: A Discursive Dictionary (Washington, DC: The Catholic University of America Press, 2020), 90.
Today, there are six suburbicarian sees. In previous eras, Rome was divided up into sometimes more and sometimes less than seven. See Johannes Baptist Sägmüller, The Catholic Encyclopedia, vol. 3 (New York: Robert Appleton Company, 1908), s.v. “Cardinal.” Available here.
Michael Walsh, The Cardinals: Thirteen Centuries of the Men Behind the Papal Throne (Grand Rapids, MI: William B. Eerdmans Publishing Company, 2010), 2-3.
Glenn D. Kittler, The Papal Princes (New York: Dell Publishing, 1961), 19.
Walsh, The Cardinals, 2.
See Walsh, The Cardinals, 2.