A precondition for regulating the finances of the Roman Empire and for overcoming the 3rd century economic crisis was the reform of the monetary system. Constantine the Great continued Diocletian's monetary reform policy and created the foundations of the Byzantine economy by introducing the nomisma (Lat: solidus). The nomisma was made up of 1/72 litra (Lat: libra; pound) of gold and weighed 4.54 grammes. Smaller denominations of the solidus were also in gold, the semisses representing half the value of the nomisma and the tremisses one third. The currency also had silver and bronze denominations. The miliaresia and the keratia were silver coins equivalent to 1/12th and 1/24th of a solidus respectfully. The bronze follis was equivalent to 1/288th of a nomisma. A bronze coin of even smaller value, the nummus (whose value fluctuated) was employed in everyday transactions.

The economic crisis that followed the political catastrophes of the 5th century and the loss of the western part of the Empire shook up Constantine's monetary system. Around 498 AD Emperor Anastasios I introduced reforms for this reason. He tried to adapt the nominal value of the follis to its true metal content in relation to the gold nomisma by issuing coins of 40, 20, 10 and 5 nummi in order to stabilize Constantine's monetary system. A certain instability occurred a little later with the coin issues of Justinian I, yet the Byzantine gold nomisma survived intact into the 11th century, providing stability not only for Byzantine but also for international trade.