Siege of Tyana (272)

Palmyra at its zenith in 271

In 269, while Claudius Gothicus (Gallienus' successor) was defending the borders of Italy and the Balkans against Germanic invasions, Palmyrene queen Zenobia was cementing her authority; Roman officials in the East were caught between loyalty to the emperor and Zenobia's increasing demands for allegiance.[6] The timing and rationale of the queen's decision to use military force to strengthen her authority in the East is unclear;[6] scholar Gary K. Young suggested that Roman officials refused to recognize Palmyrene authority, and Zenobia's expeditions were intended to maintain Palmyrene dominance.[7] Another factor may have been the weakness of Roman central authority and its corresponding inability to protect the provinces, which probably convinced Zenobia that the only way to maintain stability in the East was to control the region directly.[7]

The historian Jacques Schwartz tied Zenobia's actions to her desire to protect Palmyra's economic interests, which were threatened by Rome's failure to protect the provinces.[8] Also, according to Schwartz, the economic interests conflicted; Bostra and Egypt received trade which would have otherwise passed through Palmyra.[9] The Tanukhids near Bostra and the merchants of Alexandria probably attempted to rid themselves of Palmyrene domination, triggering a military response from Zenobia.[9]

In October of 270,[10] a Palmyrene army of 70,000 invaded Egypt,[11][12] and declared Zenobia, Vaballathus's mother, the Queen of Egypt.[13] The Roman general Tenagino Probus was able to regain Alexandria in November, but was defeated and escaped to the fortress of Babylon, where he was besieged and killed by Zabdas, a Palmyrene general, who continued his march south and secured Egypt.[14] Afterward, in 271, Zabbai, another Palmyrene general serving Zenobia, started the operations in Anatolia, and was joined by Zabdas in the spring of that year.[15] The Palmyrenes subdued the Asian province of Galatia,[16] and occupied the regional capital of Ancyra, marking the greatest extent of the Palmyrene expansion.[17]

Tyana was a great victory, which was accomplished with very little effort by the Romans. Prior to the siege, Aurelian had destroyed every city that resisted him, but he spared Tyana. Whatever the reason for his clemency, Aurelian sparing of Tyana paid off: many more cities submitted to him upon seeing that the emperor would not exact revenge upon them.

The gains made by his legions allowed Aurelian to rapidly capture significant amounts of territory taken by the Palmyrenes and eventually defeat Queen Zenobia along with subsequently diminishing and weakening the rest of the Palmyrene Empire in just six months. The war against the Palmyrene Empire only lasted for three years in total with Aurelian rising to power in 270 CE.