gold nomisma (or solidus,, a word dervied from the 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, but only rarely, for exceptionally large commercial transactions. The nomisma was equivalent to almost eighteen days labour by a worker. According to the law, every man who possessed 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 the everyday currency: a city worker made only fifteen to sixteen pholles daily; a peasant only twelve.
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 gold units of currency valued at 1/2 or 1/3 of a nomisma named semisses and tremisses respectively. Similarly, there were two silver coins: the miliaresion equivalent to twenty-four pholleis or 1/12 a gold nomisma, and the keration, worth half a miliaresion. The smaller currencies were copper subdivisions of the phollis: the half pholles and the nummia (nummi from the Latin).