Few ancient exclamations inspire the internet as much as io Saturnalia, allegedly shouted by the Romans in the streets during their celebration of the Saturnalia (and as it is December 18th today as I write this, we are already bang in the middle of that particular holiday!).

But what do we actually know about this exclamation?

Very little, it turns out.

The idea that io Saturnalia was indeed shouted widely among the population of Rome is derived from a very small number of ancient sources. The usual point of departure for conclusions regarding this practice is a short passage in the first book of the late antique author Macrobius‘ Saturnalia:

Ex his ergo omnibus colligi potest et uno die Saturnalia fuisse et non nisi quarto decimo Kalendarum Ianuariarum celebrata: quo solo die apud aedem Saturni convivio dissoluto Saturnalia clamitabantur: qui dies nunc Opalibus inter Saturnalia deputatur, cum primum Saturno pariter et Opi fuerit ascriptus.

‘From all this, then, we can conclude both that the Saturnalia comprised a single day and that it was the fourteenth day before the Kalends of January: on that day alone the Saturnalia used to be proclaimed in the temple of Saturn in the course of a relaxed banquet. That day is now assigned to the Opalia, in the course of the Saturnalia, though it was originally assigned both to Ops and to Saturn.’

Macrobius, Saturnalia 1.10.18 (transl. R. A. Kaster)

Not much in terms of the cry io Saturnalia, in fact, but still: this is the passage that is most commonly relied on.

A second passage that must be thrown into the mix comes from the Greek historian Cassius Dio, who writes about this practice in passing in the context of a debate of the year A. D. 43 over a possible military campaign in Britain:

τότε γὰρ πολλῷ που μᾶλλον ἐπ᾿ αὐτῷ ἀχθεσθέντες οὔτε τι ἐκείνῳ εἰπεῖν ἐπέτρεψαν, συμβοήσαντες ἐξαίφνης τοῦτο δὴ τὸ θρυλούμενον “ἰὼ σατουρνάλια,” ἐπειδήπερ ἐν τοῖς Κρoνίοις οἱ δοῦλοι τὸ τῶν δεσποτῶν σχῆμα μεταλαμβάνοντες ἑορτάζουσι, καὶ τῷ Πλαυτίῳ εὐθὺς ἑκούσιοι συνέσποντο.

Then they became much angrier at this and would not allow Narcissus to say a word, but suddenly shouted with one accord the well-known cry, “Io Saturnalia” (for at the festival of Saturn the slaves don their masters’ dress and hold festival), and at once right willingly followed Plautius.

Cassius Dio 60.19.3 (transl. E. Cary – H. B. Foster)

Still not much in terms of what actually used to happen on Saturnalia – but at least the missing io has now been found.

With that there are a mere three more passages that can be adduced, none of them especially helpful.

The first one comes from Petronius:

Post hoc dictum Giton, qui ad pedes stabat, risum iam diu compressum etiam indecenter effudit. Quod cum animadvertisset adversarius Ascylti, flexit convicium in puerum et “Tu autem” inquit “etiam tu rides, caepa cirrata? Io Saturnalia, rogo, mensis december est? Quando vicesimam numerasti?

At this remark Giton, who was standing by my feet, burst out with an unseemly laugh, which he had now been holding in for a long while. Ascyltos’s enemy noticed him, and turned his abuse on to the boy. “What,” he said, “are you laughing too, you curly-headed onion? Merry Saturnalia indeed: what, have we December here? When did you pay five per cent on your freedom?

Petronius, Saturnalia 58 (transl. M. Heseltine – W. H. D. Rouse)

The second one is in Martial:

Triste supercilium durique severa Catonis
frons et aratoris filia Fabricia
et personati fastus et regula morum,
quidquid et in tenebris non sumus, ite foras.
clamant ecce mei ‘Io Saturnalia’ versus:
et licet et sub te praeside, Nerva, libet.
lectores tetrici salebrosum ediscite Santram:
nil mihi vobiscum est: iste liber meus est.

Gloomy brow and stern countenance of unbending Cato and Fabricia, the plowman’s daughter, and pride in its mask, and moral code, and everything that in the dark we are not: out you go. Look, my verses shout “Hurrah for the Saturnalia!” Under your rule, Nerva, it’s allowed, and it’s our pleasure. You austere readers learn jerky Santra by heart, I am not concerned with you. This book is mine.

Martial 11.2 (transl. D. R. Shackleton Bailey)

And, finally, there is an obscure graffito from Pompeii:

Saturnina
io Saturnalia

CIL IV 2005a

Aaaaaand that’s it (I think…: if you are aware of passages specifically mention this cry that I’ve missed, please do let me know, and I shall stand corrected)!

These few passages leave little doubt over the festive character of the cheer, io Saturnalia!

Was it in common use? Clearly (or so Cassius Dio makes us believe).

Was it proclaimed in the context of the celebrations in the Saturn temple on December 19th, and used widely in the street, as a cheer or greeting? Possibly, but we have no evidence of that.

But what Cassius Dio, Petronius, and Martial all have in common is that the cry was understood to celebrate the (albeit temporary) liberation of underlings and servants against the rule of the high and mighty.

And that is a pretty good message for the season.

So go and shout it from the roof-tops (without disregarding relevant health-and-safety notices, of course!):

Io Saturnalia!