Coinage in the Byzantine Empire
Inspiring many features of these transient coinages, but outliving them all, stood the currency of the Byzantine Empire. It was based on the gold solidus (1/72 of a pound) of Constantine—the bezant of 4.5 grams (about 70 grains) maximum, which dominated so much of European trade to the 13th century. Until the 10th century, halves and thirds were also used. This gold was proverbial for its purity until the 10th century. The fundamentally religious nature of the empire was fully reflected in the coinage: throughout 10 centuries there was scarcely a single issue that did not look directly to the Christian faith, since apart from reverse types and legends, which were purely religious, the obverses showed the emperors as specifically Christian rulers by the use of adjuncts or appropriate inscriptions.
Byzantine coinage began effectively with the reign (491–518) of Anastasius I. Thenceforth, it consisted, in addition to gold, of silver and bronze. Silver, always rather rare, consisted of the small siliqua (1/24 of a solidus) or keration, followed by the larger miliaresion and the still larger hexagram. Bronze was in most periods very commonly struck. Its appearance and tariffing were reformed by Anastasius, who issued large pieces marked M, K, I, and E (equal to 40, 20, 10, and five nummi); other multiples were found either later or locally, as IB (equal to 12 nummi) at Alexandria. Such marks of value continued until Basil I (867–886). Constantinople itself was the main mint in all three metals, which were coined also at Carthage and Ravenna. Thessalonica, Nicomedia, Cyzicus, Antioch, and Alexandria struck bronze only; at one time or another Rome struck gold and bronze, while Syracuse and Catana also contributed. The technique of gold and silver minting was generally high; that of bronze was coarse, and overstriking was common.