It is very probable that Papak took the royal throne of Istakhr between the years 205/206 and 211/212 and appointed his son Shapur for it; then in an insurgent action, Ardashir moved to Gur (Ardashir-Khwarrah or current Firuzabad) from Darabgard and raised his defense fortifications there in order to be able to attack his older brother just after the death of his father, Papak. "The first inscription of Ardashir's quest of the crown" in Firuzabad is probably the symbol of his rebellion against his father and brother. Papak probably died in about 211/212 and it is after that when his two sons (Shapur and Ardashir) minted coins titled "The Shah" and decorated them with the face of their recently deceased father (Papak) behind. The report of Zin-el-Akhbar also confirms that Ardashir was crowned as a local shah in 211/212. The events of 211/212, which contain the defeat of Shapur (Ardashir's brother) and his probable murder, might be related to Ardashir's second inscription on Naqsh-e Rajab and also minting coins without the Papak's face. The writing of the phrase "his majesty worshiping Mazda, Ardashir the Persian Shah" on some second group of coins of Ardashir's might have been after his conquest of Istakhr and taking control of Pars. Ardashir's conquest of Pars and taking the adjacent lands was a threat for Artabanus; therefore, Artabanus defied Ardashir and eventually lost the Battle of Hormozdgan and was killed. It was after that when Ardashir was able to claim being "the Shahanshah of Iranians". Ardashir carved a memorial inscription for victory in the Battle of Hormozdgan near the city Gur. The signs of these events (the period between taking Istakhr until conquering Ctesiphon and formal coronation there) are shown in the inscription of Ardashir's coronation in Naqsh-e Rostam and also the alteration of his coins. Reign infrastructure The procedure of centralization of power The history of the Sasanian society can be studied based on two completely opposite principles; one was the central power, whose incarnation was the "shahanshah" himself and constantly attempted to increase his power; and on the other hand was the liegemen and grand landlords who prevented the centralization of power by the shahanshah and sometimes increased their own powers against the shah. At first, the Sasanian policies were formed based on the relations between the shah, the royal family and the noble landlords (including members of the old Parthian high class).