AD 310

Creation of the solidus by Constantine

After the eco­nomic dis­ruption caused by the infla­tionary crisis of the 3rd century AD, Emperor Con­stantine decided to reform the mon­etary system in order to restore sta­bility. In AD 310, he began to issue a new gold coin called the solidus, whose name, derived from the Latin for solid, clearly reflected the emperor’s desire to sta­bilise the currency.

In AD 312, the weight of the solidus was set at 4.55g, rep­res­enting a devalu­ation of around 15% com­pared to the Dio­cletian aurelus. It con­tinued to be used throughout the Byz­antine Empire up until the 10th century, and its weight remained unchanged. Con­stantine ensured there was a suf­fi­cient supply of gold to issue the solidus through the seizure of war booty from his enemy Licinius, the con­fis­cation of gold from pagan temples and the applic­ation of new taxes that were payable in gold. The solidus was the corner­stone of the new Roman mon­etary system throughout the 4th and 5th centuries.