The eras relating to Yazdegerd III that had been used on Arab-Sassanian coins
(incl. on the coins issued by the Arabic governors in Tabaristan)

The Sasanian, or Sassanid, Empire existed from 224 to 651 A.D.; back in the beginning of the VII-th century it occupied rather vast territory (see map 1 and map 2 for more details).

As we all know, the Sassanid Empire ceased to exist in 651 A.D. with the death of Shahin Shah Yazdegerd III. In the Middle Ages, the Zoroastrians used the chronology of the Yazdegerd Era (YE), which was started on June 16^th, 632 A.D., as well as the Post-Yazdegerd Era (PYE) — its starting point took place on June 11^th, 652 A.D. — with the when the 1^st Zoroastrian year began after the death of Yazdegerd III.

As for the dates on the Arab-Sassanian coins, Stephen Album in his catalogue [source: 1, page 25] says: the mint and date are almost always rendered in the Middle Persian Inscriptional Pahlavi script on the reverse, to the right and left of the standing attendants, respectively. The mint is normally abbreviated, whereas the date is almost always written out in full. Three (3) different dating systems are employed on the Arab-Sassanian coins, incl. on the coins issued by the Arabic governors in Tabaristan (see Tabaristan's location on the map: map 1, map 2):

1. «Regnal years of Yazdegerd» (Yazdegerd Era → abbreviated YE), counted from the first year of reign of Yazdegerd III;
2. “Regnal” years commencing with the death of Yazdigerd III («Post-Yazdegerd Era» → abbreviated PYE), counted from the year of death of Yazdegerd III;
3. (Lunar) Hijri years (more on Lunar Hejira see here).

For ease of perception and convenience of comparing the years of the three eras (PYE; YE; Lunar Hejira [A.H.]) with the years of the Gregorian calendar, here is a reference table below. This particular table was borrowed from John Walker's 1941 catalog of Arab-Sassanian coins [source: 2, pages 237–238]:

Sources:

1. Stephen Album — «Checklist of Islamic Coins», 3^rd Edition (2011);

2. John Walker, M.A. — «A catalogue of the Arab-Sassanian coins (Umaiyad governors in the East, Arab-Ephthalites, Abbasid governors in Tabaristan and Bukhara)», 1941.

This article was published on December 13^th, 2022.