Passage: The Romans were well aware that their victory was still fragile, and that as soon as the Parthian king had dealt with the Hyrcanian rebellion, he would turn his attention to Armenia. Despite Vologases' reluctance to risk an all-out conflict with Rome, in the end, he was forced to act when Tigranes raided the Parthian province of Adiabene in 61. The enraged protests of its governor Monobazus, and his pleas for protection, could not be ignored by Vologases, whose prestige and royal authority were at stake. Vologases therefore hastily concluded a treaty with the Hyrcanians so as to be free to campaign against Rome, and called an assembly of the grandees of his realm. There he publicly reaffirmed Tiridates' position as king of Armenia by crowning him with a diadem. In order to reinstall his brother on the Armenian throne, the Parthian king assembled a force of picked cavalry under Monaeses, complemented by infantry from Adiabene.In response, Corbulo sent the legions IV Scythica and XII Fulminata to Armenia, while he detailed the three other legions under his command (III Gallica, VI Ferrata and XV Apollinaris) to fortify the line of the river Euphrates, fearing that the Parthians might invade Syria. At the same time, he petitioned Nero to appoint a separate legate for Cappadocia, with the responsibility for conducting the war in Armenia.

Question: What did the Parthian king have to do before focusing on Armenia?
dealt with the Hyrcanian rebellion