it was called a solidus, which came back during the reign of Emperor Constantine the Great.

this is a solidus sign " / "

In the Roman Empire the solidus was a Roman gold coin which replaced the silver denarius as the main currency unit of the Roman Empire. In the British Commonwealth, before decimalisation, it was a punctuation mark used to denote the shilling and was also called the shilling mark.

In the Roman Empire the solidus was a Roman gold coin which replaced the silver denarius as the main currency unit of the Roman Empire. In the British Commonwealth, before decimalisation, it was a punctuation mark used to denote the shilling and was also called the shilling mark.

The Romans did not stop using gold and silver in their coins. There was continuous debasement (reduction of the precious metal content) of the gold and silver coins to the point that they became worthless. The gold and silver content became minimal, however, the use of these two mentals was not actually stopped. This caused hyperinflation. To address this problem Diocletian reformed the Roman coin system and introduced a new gold coin (the solidus) and a new silver one (the argenteus, valued at 1/10 of a solidus) which had a much higher precious metal content. His successor Constantine suspended the issuing of the silver coin to concentrate on minting large quantities of the solidus, which became the standard of the Roman currency system. He then introduced two new silver coins, the millarense (valued at 1/12 of a solidus) and the siliqua (valued at 1/24 of a solidus).