What Is The Controversy Surrounding The Attribution Of Parthian Coins?

Perhaps it shouldn't come as a surprise that in a series where rulers' personal names were rarely spelled out on their coins, attributions of some issues are pretty speculative and are occasionally updated based on current research. Most of the updating over the past twenty years has been done by G. R. F. Assar. He's written numerous articles about the Parthian chronology and coin attributions during that span, but the best encapsulation of his work is his essay "Iran Under the Arsakids, 247 BC - AD 224/227" in the Numismatic Art of Persia: The Sunrise Collection, Part I.

Assar respects most of Sellwood's attributions, but differs on some. Parthia.com recently posted a long overdue update to their correlation chart, adding a Sunrise/Assar column, which makes spotting the adjustments easy: http://parthia.com/parthia_corr.htm