The citadel, however, which had been closed by an intrepid band of youths, was not stormed without a struggle They even ventured on an engagement under the walls, but were driven back within their fortifications and succumbed at last only to our siege-works and to the swords of furious assailants. The success was the easier, as the Parthians were distracted by a war with the Hyrcanians, who had sent to the Roman emperor, imploring alliance, and pointing to the fact that they were detaining Vologeses as a pledge of amity. When these envoys were on their way home, Corbulo, to save them from being intercepted by the enemy's picquets after their passage of the Euphrates, gave them an escort, and conducted them to the shores of the Red Sea, whence, avoiding Parthian territory, they returned to their native possessions.