All adults in Byzantium used money only occasionally in order to pay their taxes or for their commercial transactions. The emperors consistently minted two types of currency: the golden nomisma (or solidus, from Latin) and the phollis which was made of copper. This monetary system was preserved unaltered until the 12th century and this is the reason why it was the only international means of transaction.

The golden nomisma was the base of the Byzantine monetary system and was used for large scale transactions, such as for the payment of taxes or of the state officials salaries, also -rarely - for some extremely large commercial transactions. The nomisma was equivalent to almost 18 days labor by a worker. According to the law, every man who pocessed a fortune over 144 nomismata (the equivalent of two pounds of gold) was considered rich.

The copper phollis was a currency of much lesser value used for everyday transactions. 288 pholles corresponded to one gold nomisma. Despite its much lower value, for a poor man it was a currency of price: a city worker made only 15-16 pholles daily; a peasant only 12. As for the value of this currency in terms of everyday life, one phollis was the normal price for a loaf of bread.

Transactions were facilitated by means of minting other currencies, subdivisions of the nomisma, that bridged the gap between it and the phollis. Therefore, there were two golden units of currency valued at 1/2 or 1/3 of a nomisma named semisses and tremissesrespectivelly. Also there were two silver ones: the miliaresion equivalent to 24 pholles or 1/12 of a gold nomisma and the keration that worth half a miliaresion. The smaller currencies were copper subdivisions of the phollis: the half pholles and the nummia (nummi, from Latin).