The Byzantine Empire derived from the Eastern half of the Roman Empire. It survived the collapse of classical antiquity, unlike the Western Roman half. While the rest of the world was minting nummus and other tiny coins, the Byzantines brought back the sestertius with their 25-45mm follis and had reliable gold coinage. The first emperor Anastasius provided economic security to the state and laid the groundwork for large scale conquest by the emperor Justinian.

This stability and the production of large quality coins lasted until the rise of the Islamic caliphates under the reign of Heraclius. The craftsmanship and metal content of the coinage plummets as the dark ages sweep over the empire. The coinage of the next 300 years is a fascinating insight into a time period with little surviving written history or literature. 650-950 AD are regarded as the darkest of the dark ages and the surviving coinage is rare and riddled with surface and strike issues.

The High Middle Age fuel the rebirth of well crafted and mass produced Byzantine coinage. Most notable of the period are the Anonymous Folli, a large sestertius style coin featuring gorgeous portraiture of Jesus and no indication of the ruling authority.

The Byzantine empire switches to producing small cup shaped coins just before Constantinople’s first sack by the Fourth Crusade in 1204 AD. They regain their capital for the next 250 years until the Ottoman Empire arrives, but their coinage of this period is worse in craftsmanship than any other time.