his father's lifetime, it is unimaginable that Odaenathus was simply a king while his son was the King of Kings. An undated inscription, written in Greek and difficult to decipher, found on a stone reused in the Palmyrene Camp of Diocletian, addresses Odaenathus as King of Kings (Rex regum) and was probably set during his reign. According to the dedication, Herodianus was crowned near the Orontes, which indicates a ceremony taking place in Antioch on the Orontes, the metropolis of Syria. The title was a symbol of legitimacy in the East, dating back to the Assyrians, then the Achaemenids, who used it to symbolize their supremacy over all other rulers; it was later adopted by the Parthian monarchs to legitimize their conquests. The first Sassanian monarch, Ardashir I, adopted the title following his victory over the Parthians. Odaenathus' son was crowned with a diadem and a tiara; the choice of Antioch on the Orontes was probably meant to demonstrate that the Palmyrene monarchs were now the successors of the Seleucid and Iranian rulers who had controlled Syria and Mesopotamia in the past. Relation with Rome In analyzing the rise of Odaenathus and his complicated relationship with Rome, the historian Gary K. Young concluded that "to search for any kind of regularity or normality in such a situation is clearly pointless". In practice, Palmyra became an allied kingdom of Rome, but legally, it remained part of the empire. The "King of Kings" title was probably not aimed at the position of the Roman emperor but at Shapur I; Odaenathus was declaring that he, not the Persian monarch, was the legitimate King of Kings of the East. Odaenathus' intentions are questioned by some historians, such as Drinkwater, who attributed the attempted negotiations with Shapur I to Odaenathus' quest for power. However, in contrast to the norm of this period when powerful generals frequently proclaimed themselves emperors, Odaenathus chose not to attempt to usurp Gallienus' throne. The relationship between Odaenathus and the Emperor should be understood from two different perspectives: Roman and Syrian. In Rome, broad power delegation by the Emperor to an individual from outside the imperial family was not considered a problem; such authority had been granted several times since the days of Augustus in the first century. The Syrian perspective was different: according to Potter, the dedication celebrating Herodianus' coronation on the Orontes should be interpreted to mean a "Palmyrene