A date close to the end of the Aškānian period is found in the stele of Xvasag. Ašk. 462 – 247 = A.D. 215/216. In fact the monument belongs to the third year of the last Aškānian king, Ardavān. According to the Šābūragān Mani was born in the year 527 of the era of the Babylonian astronomers, in the 4th year of the king Ardavān. This establishes Ardavān’s accession in SB 524, that is, A.D. 213/214. The Ardavān’s first year began June 1, 213, Tuesday (day Ohrmazd, month Fravardīn).
Here is the Parthian inscription of the last Arsacid king, discovered at Susa in 1947:
Ardaβān šāhān šāh puhr Valaγš šāhān šāh BNYt / dišt / ḥnsk /xansāg/ ēd cē ḥwsk /Xvasag/ Šūš xšaθrab sard iiii c xx xx xx ii māh spendarmad rōž miθr.
‘Ardaβān, king of kings, son of Valaγš, king of kings, built this strong building, (which is) that of Xvasag, satrap of Susa. Year 462, month of Spəṇtā Ārmaiti, day of Miθra.’
The Aškānian “Royal” year 462 began on Thursday, June 1, 215. The day Miθra of the Month Spəṇtā Ārmaiti of that year corresponds to May 12, 216, Sunday.