If the reading of the oldest manuscript of Pliny, in the passage where he deals with the first issue of the denarius nummus at Rome, is accepted, a problem arises centring round the term bigati. Briefly, the difficulty is this :—

Pliny says that the denarius nummus was first struck at a date which works out as 217 B.C.

Livy states that thousands of bigati were taken as booty in Cisalpine Gaul in 197 and 196 B.C., and in Spain in 195 and 191 B.C.

There is no doubt as to what the denarius nummus was : it was the silver coin bearing the mark X which gave it the official currency-value of ten asses, and was the prototype of the long series of coins which were known and current as denarii under the Republic and Empire. Having a face-value, it was rightly distinguished as a nummus from the earlier silver coins whose currency-value might and did vary in relation to the bronze nummus, the as : these had in the first instance been rated at ten asses and called denarii, but by 217 their exchange rate was sixteen asses.