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…