De Verborum Significatu

Sextus Pompeius Festus

Saturn quoque dicebantur, qui castrum in imo clivo Capitolino incolebant, ubi ara dicata ei deo ante bellum Troianum videtur, quia apud eam supplicant apertis capitis.

And those people who inhabited the camp on the lowest slope of the Capitoline were also called Saturni; there an altar seems to have been dedicated to that god before the Trojan War, because they pray before it with their heads uncovered.

Translation by Jane W. Crawford, © 2001.