CLAVUS Annalis, in Antiquity. So rude and ignorant were the Romans at the rise of their state, that the driving or fixing a nail was the only method they had of keeping a register of time; for which reason it was called clavis annalis. There was an ancient law, ordaining the chief praetor to fix a nail every year on the ides of September; it was driven into the right side of the temple of Jupiter Optimus Maximus, towards Minerva's temple. This custom of keeping an account of time by means of fixing nails was not peculiar to the Romans; for, with the same view, the Etrurians used likewise to drive nails into the temple of their goddess Nortia.