Under Justinian we again find some small traces of a national coinage in Egypt. Ever since the reign of Diocletian, the old Egyptian coinage had been stopped, and the Alexandrians had used money of the same weight, and with the same Latin inscriptions, as the rest of the empire. But under Justinian, though the inscriptions on the coins are still Latin, they have the name of the city in Greek letters. Like the coins of Constantinople, they have a cross, the emblem of Christianity; but while the other coins of the empire have the Greek numeral letters, E, I, K, A, or M, to denote the value, meaning 5, 10, 20, 30, or 40, the coins of Alexandria have the letters 1 B for 12, showing that they were on a different system of weights from those of Constantinople. On these the head of the emperor is in profile. But later in his reign the style was changed, the coins were made larger, and the head of the emperor had a front face. On these larger coins the numeral letters are [A r] for 33. We thus learn that the Alexandrians at this time paid and received money rather by weight than by tale, and avoided all depreciation of the currency. As the early coins marked 12 had become lighter by wear, those which were meant to be of about three times their value were marked 33. During the period from 566 to 602 Justin II. reigned twelve years, Tiberius reigned four years, and Mauricius, his son-in-law, twenty; and under these sovereigns the empire gained a little rest from its enemies by a rebellion among the Persians, which at last overthrew their king Chosroes. He fled to Mauricius for help, and was by him restored to his throne, after which the two kingdoms remained at peace to the end of his reign. [Illustration: 316.jpg COINS OF JUSTINIAN] The Emperor Mauricius was murdered by Phocas, who, in 602, succeeded him on the throne of Constantinople. No sooner did the news of his death reach Persia than Chosroes, the son of Hormuz, who had married Maria, the daughter of Mauricius, declared the treaty with the Romans at an end, and moved his forces against the new emperor, the murderer of his father-in-law. During the whole of his reign Constantinople was kept in a state of alarm and almost of siege by the Persians; and the crimes and misfortunes of Phocas alike prepared his subjects for a revolt. In the seventh year Alexandria rebelled in favour of the young Heraclius, son of the late prefect of Cyrene; and the patriarch of Egypt was slain in the struggle. Soon afterwards Heraclius entered the port of Constantinople with his fleet, and Phocas was put to death after an unfortunate reign of eight years, in which he had lost every province of the empire.