Byzantine Empire, Justinian I (527-565 AD), Bronze Follis, Year 22 of Justinian's rule (548/549). Weight: 20.47 g. Diameter: 34 mm. This bronze coin, called follis was minted in Constantinople in 538 AD. 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. The obverse of our follis portrays Justinian I, who renewed the Roman Empire, though not to its full former extent and only for a short time. The church of San Vitale in Ravenna is a still visible mark of his victory over the Germanic kings in Italy. Justinian also founded the Christian church that today is a famous mosque, the Hagia Sophia. Another of Justinian's achievements, together with his wife Theodora, were major contributions to Byzantine legislation.