Byzantine Empire, Justinian I, Follis

This bronze coin called follis was minted in Constantinople in 548. Remarkable is the capital "M" on the reverse – one of the few indications of value on antique coins. It is by no means a coincidence that smaller denominations from debased metals were the first ones to show indications of values. The "M" on this coin stood for "40 nummi." Smaller fractions of the follis were also known, showing the letters "K," "I" and "E." 180 follis equaled a solidus, the most frequent gold coin of those days.