Ambrosius Theodosius Macrobius

Ait enim nundinas Iovis ferias esse, siquidem flaminica omnibus nundinis in regia Iovi arietem soleat immolare, sed lege Hortensia effectum ut fastae essent, uti rustici, qui nundinandi causa in urbem veniebant, lites componerent.

For he says that the market days of Jove are holidays, since the flamen's wife is accustomed to sacrifice a ram to Jove in the Regia every market day, but it was enacted by the Hortensian law that they be days on which courts could be held, so that the country people, who come to the city for the sake of the markets, could prepare law suits.

Translation by Jane W. Crawford, © 2001.