For this patron several of his treatises were written; and the commencement of his Canon of Medicine also dates from his stay in Hyrcania.
Tiridates, who was proclaimed king, could no longer maintain himself, because he appeared to be a vassal of the Romans; Artabanus returned from Hyrcania with a strong army of Scythian (Dahan) auxiliaries, and was again acknowledged by the Parthians.
In 209 Antiochus invaded Parthia, occupied the capital Hecatompylus and pushed forward into Hyrcania.
The governors appointed by Alexander were, in the west of the empire, exclusively Macedonians; in the east, members of the Old Persian nobility were still among the satraps at Alexander's death, Atropates in Media, Phrataphernes in Parthia and Hyrcania, 1 For the events which brought this empire into being see Alexander The Great.
Hyrcania, also, revolted and asserted its independence under a separate line of kings.