Money is the only human invention capable of embodying both dreams and reality in an indissoluble bond; it is the abstract distributor of hope and a concrete means of controlling the lives of human beings and nations.
From its first appearance in the Near East in the form of shiny little metal spheres, money has long been entrusted with the fates and fame of great kings, such as King Croesus (hence the saying, “as rich as Croesus”). The same is true of cities famous beyond the borders of the known world at that time: Athens, Corinth, and Aegina. In a world that measured time against the ancient Olympic games, the Croesus coins, Athenian Owls, Pegasus coins, and Aegean Turtles united different peoples in bonds made permanent by economic interests, often backed up by military force.

This period was doomed to be short, flames that soon died out under the ashes of time. With his seemingly unstoppable army, Alexander the Great, had managed to create and implement a single monetary system in Greece, Asia Minor, Syria, Egypt, Babylonia and beyond, which was well organised into three metals (gold, silver and bronze) with coins of identical weight and type for people who were very different from one another. Yet even this dream of his floundered on the banks of the Euphrates river at the end of spring 323 BC.  After Alexander’s death, the political break-up of the territories he had conquered led to the unravelling of a monetary system that had not had enough time to grow deep roots in Asia.

Events took a different turn with Rome. The unification of Roman territories, with political and administrative control of provinces in Europe, Asia and Africa, ensured that conditions were in place for Roman currency to become implemented in systematic, profound manner in every corner of the vast Empire. First there were denarii, aurei and later sestertia; these became the tangible sign of a strong, well-organised central power able to control and unify highly diverse territories, cultures, economies and social fabrics. The Legions of the Roman Republic brought the silver denarius bearing the head of the Goddess Roma to newly conquered lands. Subsequently, Roman magistrates were sent by the Roman people and Senate or Emperor (as was the case) to ensure that a well-organised society (where even old, local coins could still be used for minor daily errands) would be centered on Roman currency. This situation held strong for over seven centuries, thanks to a dynamic power that survived pressure from the Barbarians and the transfer of Imperial insignia to Constantinople in 476 AD.  
Indeed, the gold solidus (or Byzantine coin) – a pure metal coin created by Constantine in the early 4th century AD in order to reverse the free fall of the old, glorious yet unsalvageable denarius, continued to function as an international currency. However, the times had changed for good. It was no longer the unifying authority of a strong State that guaranteed the currency’s success; it was the “faith” of different peoples and market mechanisms, rather than political rule, that did so.
Thus the Byzantine coin continued to perform its role along ancient Mediterranean routes, making its way through the dark Middle Ages and imitated by Goths, Lombards, Arabs and Normans alike.
Meanwhile, Europe began breaking up into thousands of small territories controlled locally by castles and monasteries, until the time of Charlemagne.

Under the Carolingian Empire, the European continent returned to conditions which enabled the relaunch of a high Medieval European “single currency”, as we would label it today: the silver denier. Although different in weight and alloy,