Unfortunately, our knowledge of the pre-Sasanian history of Persis is almost a total blank save for what is known from coins struck by local dynasts. At least one local kingdom had existed in the heart of Persis since the breakup of Seleucid power in Iran, if not earlier, from shortly after the death of Alexander the Great. The ruins of Persepolis and Pasargadae alone would have been a standing reminder of the past glory of the area, even if knowledge of a great empire for the most part had been forgotten.2 The names (such as Darius and Artaxerxes) on the coins of the local rulers who held sway here before the rise of the Sasanians testify to a certain continuity of Achaemenian traditions, if not to an actual descent in a side line from the royal Achaemenian family itself. The history of the immediate predecessors of Ardashlr is thus virtually unknown and the few items of information about them are conflicting.
Most scholars have assumed, following the Arabic history by Tabari, that Sasan was the grandfather and Papak the father of Ardashlr, founder of the Sasanian dynasty. The trilingual inscription (Greek, Parthian and Middle Persian) of Shapur I, on the Ka'ba-yi Zardusht at Naqsh-i Rustam, however, does not say that Sasan was the father of Papak. In an ascending order of importance, Sasan is merely designated as a lord, while Papak is a king. Ardashlr, his son, is caking of kings of Iran, while Shapur, son of Ardashir, is called king of kings of Iran and non-Iran. There is another version of the lineage of Ardashir found in a story in the Middle Persian book, the Kdr-ndmag or "Book of Deeds of Ardashir son of Papak". The same version is also given by Firdausi in his epic the Shdh-ndma and appears to be the basis of a scurrilous Greek adaptation of the tale recorded by Agathias, a sixth-century Byzantine author. This story tells how Sasan was married to the daughter of a local prince Papak after the latter learned that Sasan had royal Achaemenian blood in him. From this union Ardashir was born. Then Sasan vanishes from the story and Papak is considered the father of Ardashir. This corresponds to the inscription and other later Arabic and New Persian sources. The problem is, who was Sasan ?
One should note that Shapur's inscription does not give us the answer and for lack of another course, one may choose between the version of the epic, and the statement of Tabari that Sasan was the father of Papak. Tabarl's account, however, is suspect, since he reports a lengthy genealogy of Ardashir tracing it back to mythical, heroic kings of ancient Iran. It is more likely that Sasan was a remote ancestor of Ardashir whose name was given to the dynasty as Achaemenes was for the Achaemenids. Most plausible, however, is the epic version which may have the following interpretation: Sasan was the natural father of Ardashir, but he died shortly after the birth of his son whereupon, according to current Zoroastrian practice, Papak adopted Ardashir as his own son; or the adoption may have occurred after a certain Shapur, Papak's son, was killed.
In any case, King Papak probably united much of Fars under his sway during the hectic time of the Parthian sovereign Vologeses IV (192-207) when Septimius Severus invaded Mesopotamia and wrought havoc there. About the year 205 (or possibly 208 according to another reckoning), if we may accept this date from an inscription of Shapur on a pillar from his capital at Bishapur, which gives the date 58 with no indication of any era, something happened which started a Sasanian chronology. Because we have no sources, one can only guess at the event in Fars which led to this dating. Perhaps Papak overthrew a ruler of Stakhr at that time, or he may have decided to proclaim his independence of the Parthians at that date. Since the same inscription also mentions two other ways of dating, the fortieth year of the fire of Ardashir and the twenty-fourth year of the fire of Shapur, the conjecture that the year 58 had something to do with Papak, rather than with Ardashlr's rise to the governorship of a city, or the like, is eminently plausible. This political interpretation is also more likely than any other, such as a religious act connected with the shrine dedicated to Anahita at Stakhr, with which the early Sasanians seem to have been closely connected.2 The custom of establishing a fire temple, at least kindling a new fire at the accession of a new ruler, may have existed in Parthian times. The fire of the Sasanian monarch was extinguished at the end of his reign, a symbolic as well as religious act. In any event, a Sasanian system of dating from the year of Papak did not spread; rather the old method of dating by the regnal years of a king, or the Seleucid calendar, beginning with the year 312 B.C., became usual.
The events preceding Ardashlr's victory over Ardavan, the last of the Parthians, in c. 224, may be reconstructed from brief notices in later Islamic sources. There is a possibility that the Parthian king Vologeses IV defeated Papak, after the latter's revolt, and forced him to return to Parthian allegiance, at least for a time. It is unlikely that Papak extended his rule much beyond central Fars, and most conquests even there may have been the work of Ardashir. The date of Papak's death is unknown, but before that he was succeeded by his eldest son Shapur, who probably was killed accidentally after a very short rule. Ardashir, whose relationship to Papak we have already mentioned, became king, probably about 216, and began to expand his realm into Kirman in the east and Elymais to the west.
The overthrow of the Parthians seems to have been the result of a coalition headed by Ardashir, since the Syriac Chronicle of Arbela says that the rulers of Adiabene and Kirkuk joined Ardashir in a crusade against the Parthians which was successful. The date of the battle of Hormizdagan, in which Ardavan was killed, cannot be determined satisfactorily because of the uncertainty of the entire chronology of the early Sasanians.