The Shahanshahs of the Sasanian Empire ruled over a vast territory. At its height, the empire spanned from Turkey and Rhodes in the west to Pakistan in the east, and also included territory in contemporary Caucasus, Yemen, UAE, Oman, Egypt, Israel, Lebanon, Syria, Jordan and Central Asia. The Sasanian Empire was recognized as one of the main powers in the world alongside its neighboring arch rival, the Roman-Byzantine Empire, for a period of more than 400 years. The Sasanian dynasty began with Ardashir I in 224, who was a Persian from Istakhr, and ended with Yazdegerd III in 651. The period from 631 to 632 is confusing in determining proper succession because a number of rulers who took the throne were later removed or challenged by other members of the House of Sasan. The period was one of factionalism and division within the Sasanian Empire.
Title
, the founder of the Sassanian Empire, introduced the title "Shahanshah of the Iranians". Ardashir's immediate successor, Shapur I chooses the titles in a precise manner in the inscription at Ka'ba-ye Zartosht. In that Shapur names four of his Sasanian predecessors with different titles and in "an ascending order of importance" by giving the title "the lord" to Sasan, "the king" to Papag, "King of Kings of Iranians" to Ardashir, and "king of kings of Iranians and non-Iranians" to himself. The title "King of Kings of Iranians and non-Iranians" has also seen on a single silver coin of Shapur I, which indicates that the title was introduced after his victory over Romans and incorporation of non-Iranian lands into the Sassanian realms. The title was later used in coins of all later Sassanian kings.
The head of the Sasanian Empire was the , also simply known as the shah. His health and welfare were always important and the phrase “May you be immortal" was used to reply to him with. By looking on the Sasanian coins which appeared from the 6th-century and afterward, a moon and sun are noticeable. The meaning of the moon and sun, in the words of the Iranian historian , “suggest that the king was at the center of the world and the sun and moon revolved around him. In effect, he was the “king of the four corners of the world," which was an old Mesopotamian idea." The king saw all other rulers, such as the Romans, Turks, and Chinese, as being beneath him. The king wore colorful clothes, makeup, a heavy crown, while his beard was decorated with gold. The early Sasanian kings considered themselves of divine descent; they called themselves for “bay". When the king went to the publicity, he was hidden behind a curtain, and had some of his men in front of him, whose duty was to keep the masses away from the king and to make his way clear. When one came to the king, he/she had to prostrate before him, also known as proskynesis. The king was guarded by a group of royal guards, known as the pushtigban. On other occasions, the king was protected by a group of palace guards, known as the darigan. Both of these groups were enlisted from royal families of the Sasanian Empire, and were under the command of the hazarbed, who was in charge of the king's safety, controlled the entrance of the kings palace, presented visitors to the king, and was allowed to be given military command or used in negotiations. The hazarbed was also allowed in some cases to serve as the royal executioner. During Nowruz and Mihragan, the king would hold a speech.
Throughout its existence, the Sassanid Empire was an absolute monarchy. The Shahenshah was the height of authority, with satraps ruling over their satrapies underneath them. The shahanshah was the highest form of authority throughout the empire, but often faced rebellions from their satraps. In fact, the Sasanian Empire had been founded when a satrap rebelled against the Parthian Empire. The Sasanian Empire reached its greatest extent under Khosrow II, who reigned for 38 years; the longest reigning king was Shapur II, who reigned for 70 years. The Sasanian kings regarded themselves as successors of the Achaemenid Empire, and many Sasanian kings' goal was to conquer all territory previously held by the Achaemenids.
