The deserts in the southeast of the province of Syria were inhabited by free Arab tribes, which from the earliest times had led a roving and predatory life. Augustus acted as Pompey had done before him; he concluded a treaty and alliance with Malchus of Petra, the Nabatæan prince and successor to Aretas, and with the chieftain Iamblichus of Emesa, whose father, another Iamblichus, had been executed by Antony, guaranteeing to them the possession of their paternal inheritance on condition that they should ward off the predatory incursions of the sons of the desert. An attempt made by Ælius Gallus, governor of Egypt, to subjugate Arabia Felix in the year 24 ended miserably. The glare of the sun and the perils of the climate soon scared the invaders away and protected the natives from the Roman swords. The general of the Nabatæan prince, who had conducted the desert campaign, paid for his supposed treason with his life; but the disloyalty of the servant was not laid to his master’s charge. Rome had still an affair of honour to settle with the Parthians; the day of Carrhæ was not yet requited and the blood of Crassus and his comrades cried for vengeance. Augustus nevertheless cherished no desire to expose himself and his legions to the darts of the iron horsemen. In this instance fortune again proved his ally. Parthia and Armenia, which at that time stood in intimate relations with one another, were distracted with quarrels over the succession. Tigranes, son of the unhappy Artavasdes, appealed for Roman aid against Artaxias, the nominee of the Parthian king. Tiberius invaded Armenia with an army, and bestowed the throne on the protégé of Rome, Artaxias having been slain by the natives at the general’s coming (20 B.C.). This catastrophe filled the Parthian king with apprehensions that the Romans might declare for the pretender Tiridates, and procure for himself a like fate with Artaxias. He therefore complied with the demands of Augustus and restored the Roman ensigns and the prisoners who had been detained in the far East ever since the disaster of Carrhæ. The emperor celebrated the restoration of the eagles by a sacrificial feast, as if it had been a victory, and dedicated a temple to Mars the Avenger. But Armenia attained to no lasting tranquillity; at one time it was dominated by Roman influence, at another the Parthians gained the upper hand; kings were installed and exiled, quarrels for the throne and party feuds filled the land. Under Nero, the Parthian king Vologeses I set his brother Tiridates on the throne of Armenia, and thus fanned the embers of war between the Romans and Parthians to a blaze.