Analysis of information sources in references of the Wikipedia article "Rashidun Caliphate" in English language version.
As the Arabs of the Ḥejāz had used the drahms of the Sasanian emperors, the only silver coinage in the world at that time, it was natural for them to leave many of the Sasanian mints in operation, striking coins like those of the emperors in every detail except for the addition of brief Arabic inscriptions like besmellāh in the margins. [...] In the year 79/698 reformed Islamic dirhams with inscriptions and no images replaced the Sasanian types at nearly all mints. During this transitional period in the 690s specifically Muslim inscriptions appeared on the coins for the first time; previously Allāh (God) had been mentioned but not the prophet Moḥammad, and there had been no reference to any Islamic doctrines. Owing to civil unrest (e.g., the revolt of ʿAbd-al-Raḥmān b. Ašʿaṯ, q.v., against Ḥajjāj in 81/701), coins of Sasanian type continued to be issued at certain mints in Fārs, Kermān, and Sīstān, but by 84/703 these mints had either been closed down or converted to production of the new dirhams. The latest known Arab-Sasanian coin, an extraordinary issue, is dated 85/704-05, though some mints in the east, still outside Muslim control, continued producing imitation Arab-Sasanian types for perhaps another century.
"I Zuhair believe in God and wrote a time – Amr bin Affan in the year twenty-four".
As the Arabs of the Ḥejāz had used the drahms of the Sasanian emperors, the only silver coinage in the world at that time, it was natural for them to leave many of the Sasanian mints in operation, striking coins like those of the emperors in every detail except for the addition of brief Arabic inscriptions like besmellāh in the margins. [...] In the year 79/698 reformed Islamic dirhams with inscriptions and no images replaced the Sasanian types at nearly all mints. During this transitional period in the 690s specifically Muslim inscriptions appeared on the coins for the first time; previously Allāh (God) had been mentioned but not the prophet Moḥammad, and there had been no reference to any Islamic doctrines. Owing to civil unrest (e.g., the revolt of ʿAbd-al-Raḥmān b. Ašʿaṯ, q.v., against Ḥajjāj in 81/701), coins of Sasanian type continued to be issued at certain mints in Fārs, Kermān, and Sīstān, but by 84/703 these mints had either been closed down or converted to production of the new dirhams. The latest known Arab-Sasanian coin, an extraordinary issue, is dated 85/704-05, though some mints in the east, still outside Muslim control, continued producing imitation Arab-Sasanian types for perhaps another century.
The translation of the inscription is: I am Qays, the scribe of Abū Kutayr. Curse of God on [those] who murdered Uthman and [those who] have led to the killing without mercy.
[One scholar suggests that] the Byzantine Empire's population fell from a high of 26 million in 540 just before the outbreak of the plague, to 17 million in 610 ...
1. In the name of God 2. I, Zuhayr, wrote (this) at the time Umar died, year four 3. And twenty
As the Arabs of the Ḥejāz had used the drahms of the Sasanian emperors, the only silver coinage in the world at that time, it was natural for them to leave many of the Sasanian mints in operation, striking coins like those of the emperors in every detail except for the addition of brief Arabic inscriptions like besmellāh in the margins. [...] In the year 79/698 reformed Islamic dirhams with inscriptions and no images replaced the Sasanian types at nearly all mints. During this transitional period in the 690s specifically Muslim inscriptions appeared on the coins for the first time; previously Allāh (God) had been mentioned but not the prophet Moḥammad, and there had been no reference to any Islamic doctrines. Owing to civil unrest (e.g., the revolt of ʿAbd-al-Raḥmān b. Ašʿaṯ, q.v., against Ḥajjāj in 81/701), coins of Sasanian type continued to be issued at certain mints in Fārs, Kermān, and Sīstān, but by 84/703 these mints had either been closed down or converted to production of the new dirhams. The latest known Arab-Sasanian coin, an extraordinary issue, is dated 85/704-05, though some mints in the east, still outside Muslim control, continued producing imitation Arab-Sasanian types for perhaps another century.
As the Arabs of the Ḥejāz had used the drahms of the Sasanian emperors, the only silver coinage in the world at that time, it was natural for them to leave many of the Sasanian mints in operation, striking coins like those of the emperors in every detail except for the addition of brief Arabic inscriptions like besmellāh in the margins. [...] In the year 79/698 reformed Islamic dirhams with inscriptions and no images replaced the Sasanian types at nearly all mints. During this transitional period in the 690s specifically Muslim inscriptions appeared on the coins for the first time; previously Allāh (God) had been mentioned but not the prophet Moḥammad, and there had been no reference to any Islamic doctrines. Owing to civil unrest (e.g., the revolt of ʿAbd-al-Raḥmān b. Ašʿaṯ, q.v., against Ḥajjāj in 81/701), coins of Sasanian type continued to be issued at certain mints in Fārs, Kermān, and Sīstān, but by 84/703 these mints had either been closed down or converted to production of the new dirhams. The latest known Arab-Sasanian coin, an extraordinary issue, is dated 85/704-05, though some mints in the east, still outside Muslim control, continued producing imitation Arab-Sasanian types for perhaps another century.