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.