The following quotation is attributed to Pope Pius XII:

The day the Church abandons her universal tongue [Latin] is the day before she returns to the catacombs.

Says who?

A few notable uses of the quotation online are:

• Cream City Catholic in 2013, in a fact check article (that does not source any of its quotations)¹
• Tridentine Catholic Website, in their header image²
• Praying Latin, who source the quotation as “days before his death”³
• and Traditio in 2005, the earliest instance I can find of the quotation online, who source it as “Mediator Dei”⁴

Mediator Dei and Pius on Latin

Pius’ encyclical Mediator Dei is the source that is most commonly given for this quotation, but one will search in vain for the quotation in that document.

Pius did, of course, discuss Latin in Mediator Dei with the famous quotation:

60. The use of the Latin language, customary in a considerable portion of the Church, is a manifest and beautiful sign of unity, as well as an effective antidote for any corruption of doctrinal truth.

So the sentiment of the original quotation about catacombs is not implausible; it’s simply not confirmed. It’s not in Mediator Dei, and checking something said, “days before his death” is above my pay grade and time-traveling abilities.

Looking elsewhere

In the course of checking my usual sources and databases for any relevant keywords, I found several unrelated but interesting uses of the phrase “returns to the catacombs”:

‘Now it is not too much to say that the one key of this normal state was civil intolerance of heresy. It was the civil ruler s highest function to co-operate with the Church in preserving unshaken the firm conviction of Catholic truth, and in preserving unsullied the purity and unearthliness of Catholic sentiment.’ This state of things, never adequately realised, but effectively approached in the Middle Ages, has gone. The result is, not that the Catholic spirit is gone, but that it becomes the property of individual persons and small communities. It returns to the catacombs. It ceases to have the force of an elevating and sustaining public opinion. Faith becomes again, in a sense, more personal and less corporate. The surrounding atmosphere is unhealthy. The bracing oxygen of the mediaeval Church is supplanted by a climate not even neutral but poisonous. And this change is, he explains, the destruction of that state of things which Catholics recognise as " normal."⁵

“Man is man all the time, and not only in his spare time. In an industrial state, men, ‘working-men,’ the majority, are only fully responsible when they are not working. In such a state, Catholicism returns to the catacombs. Thence she will emerge when the orgasm of industrial triumph has spent itself.” Those who have read Eric Gill’s Money and Morals may recognize this quotation.⁶

Otherwise, I could find no quotation from Pope Pius XII that used any of the exact keywords (catacombs, universal tongue, returns to, etc.).

Did he say it?

I can’t confirm that Pope Pius XII ever said, “The day the Church abandons her universal tongue [Latin] is the day before she returns to the catacombs.” There is no evidence he said it, but it is not completely unlikely.

What I did find is a related quotation that has not made its way into any mainstream outlet, as far as I can see.

Pope Pius XII, in an Apostolic Letter, said Latin is not a dead language and must be “preserved in its force and in its clarity.” He stressed that the fact that Latin is “not covered by the dust of centuries” does not justify calling it a dead language. The Pontiff said it especially deserved to be preserved because it is an instrument which serves to provide understanding of the wisdom of the teachings of the Catholic Church.⁷

I couldn’t find any hits for those exact phrases mentioned in the newspaper clipping, so I checked the Acta Apostolicae Sedis. The closest match that I found was from a letter in May 1958, “De Latina Lingua Rite Excolenda.”

Ex omnis aetatis igitur viris litteratis exemplum simul et incitamentum capiant discipuli, qui hac ratione certis innixam argumentis hanc detegent veritatem: linguam Latinam non esse mortuum quiddam vel exsangue saeculorum pulvere contectum ideoque ad vitae disciplinam prorsus inutile, sed instrumentum atque sapientiae humanitàtisque vehiculum, quibus, Ecclesia duce et magistra, noster civilis cultus effictus et conformatus est: eam igitur iure meritoque firmam etiam hodie servare vim et efficacitatem.⁸

I asked a classicist friend to focus on phrases that I thought used “dust” and “clarity”. He translated two relevant phrases as, “that Latin is certainly not dead or buried in the lifeless dust of ages”, and “therefore rightfully and deservedly to keep this force and power enduring even today.” Given the nearly identical keywords and the date of this letter, it seems reasonable to think that this May 1958 letter from Pius (as yet untranslated in full) is the closest both to the newspaper clipping above, and perhaps may have inspired the alleged catacombs quotation.

Sources