272: Postumius Quietus, (Iunius) Veldumnianus coss. 
Zosimus provides us with the most detailed information regarding the campaigns against Palmyra. Aurelian’s army crossed Asia Minor in the spring of 272, and the cities of Ancyra, Tyana, ‘and all the other cities on the road to Antioch’ were recaptured without difficulty. If the Palmyrenes had been able to seize a large part of Anatolia, they do not seem to have been able to maintain armed forces there in sufficient numbers.
The towns and the civilian populations were lukewarm towards Palmyrene domination. As the imperial troops were crossing the Taurus and entering Syria, the rulers of Palmyra could no longer misunderstand Aurelian’s intentions and so Zenobia and Vabalathus took a final step towards usurpation by proclaiming themselves the sole Augusti.
The mints under their control, Antioch in Syria and Alexandria in Egypt, stopped striking coins in the joint names of Aurelian and Vabalathus and started striking coins exclusively for the new Augusti, Vabalathus and Zenobia: the queen thus also made her appearance on the coinage.
This final stage of the Palmyrene usurpation can be dated: the last papyrus to be redacted in the name of Aurelian year 2/Vabalathus year 5, is dated to 17 April 272. No papyri are known in the names of Vabalathus and Zenobia as Augusti. Tetradrachms exist in the name of Aurelian year 2 and sole emperor, demonstrating that Alexandria had already returned to Roman control before the regnal years of Aurelian were corrected, with his second year becoming his third. A papyrus from Oxyrhynchus (P. Oxy. 2902) in the name of Aurelian alone year 3, is dated to 24 June 272: it shows that the correction of the regnal year had occurred across the whole of Egypt by this date. The Palmyrene usurpation itself must have occurred between these dates and therefore could only have lasted a few weeks, from March to May 272 in Syria, and from mid-April to early June in Egypt.
In May 272, the Roman cavalry and that of the Palmyrenes clashed near Antioch, close to Immae. The heavy Palmyrene cavalry was defeated. On hearing the news, the army of the Palmyrene general Zabdas secretly abandoned the town of Antioch and withdrew to Emesa. The town of Antioch surrendered to Aurelian who showed clemency towards the population. The issues in the names of Vabalathus and Zenobia as Augusti immediately came to an end, to be replaced by issues in the name of Aurelian. From that point on, the emperor was no longer hailed as Restitutor Orientis, but as Restitutor Orbis, a legend which appeared first on the reverse of coins from Antioch before spreading to all the mints of the Empire from east to west.
At the same time, Egypt was recaptured by Aurelian’s generals and the mint of Alexandria returned to issuing coins in the name of Aurelian as sole emperor. The reconquest of Egypt offered the emperor the opportunity to correct his regnal years. Before 29 August 272, the date of the Egyptian new year, the Egyptian tetradrachms refer to Aurelian’s second year without Vabalathus; Egyptian documents, coins and papyri then mention his third year (ending June – August 272); finally from 29 August 272, the documents are dated to his fourth year. Aurelian thereby made up his dies imperii (accession date) before 29 August 270, in other words to the death of Claudius II, which permitted him to reduce the reign of Quintillus to a simple usurpation and to present himself as the legitimate successor of Claudius.
After Aurelian’s first successes at Antioch, the imperial army pursued the Palmyrenes along the Orontes river. Apamea, Larissa and Arethusa were retaken even more easily, as the civilians had been reassured that the Roman troops would not destroy their cities. The first and only battle between the Palmyrenes and the Roman army took place outside Emesa. Zosimus describes the composition of the Roman army as including troops from Mesopotamia, Syria, Palestine and Phoenicia, showing that, from the summer of 270, those who had been under Palmyrene command had already rallied to Aurelian’s side. At Emesa the Roman cavalry tried to repeat the tactics that had succeeded at Immae by attempting to drag along the Palmyrene cavalry behind them. However the manoeuvre nearly turned into a catastrophe for at this time the Roman infantry was engaged in the battle and the Palmyrene cavalry attacked the Romans on both aisles, threatening to encircle them. The rapid reaction of the Roman infantry, taking advantage of a quick wheel conversion to turn against the enemy’s cavalry, helped to save the situation. This military victory opened the road to Palmyra. Imperial propaganda attributed the victory at the battle of Emesa to the miraculous intervention of the Sun god.
This epiphany marked the foundation of the cult of Sol. The chronology given by the Historia Augusta is correct, since it was from the summer of 272 that the iconography of Sol, with many different coin types showing the god Sol fighting, combined with the legends Conservat Aug, Oriens Aug and Soli Invicto, were first struck at the mint at Antioch. These types then spread gradually westwards to all the mints of the Empire.
Having crossed the Syrian desert, the Roman army laid siege to Palmyra. The walls of the city at that time were just a barely defensible circuit comprising, to the north of the city, a simple earth mound, intended to protect it against attacks from the nomads but incapable of holding off an imperial army for long. Zenobia was captured while attempting to cross the Euphrates when fleeing the city. The inhabitants of Palmyra, divided on what course of action to take, finally surrendered to Aurelian, who again showed clemency. Few weeks had elapsed between the battle of Emesa in June 272 and the taking of Palmyra. An inscription from Palmyra indicates that in August 272 the town passed into Roman hands with the help of some of its notable inhabitants: the inscription honours the thiasis (the college) of the priests of Bel, ruled by the symposiarch Haddudan, whose principal claim to fame is to have ‘helped the troops of Aurelian Caesar, our master’, apparently at the surrender of the town. The inscription proves that, even in Palmyra, the reign of Zenobia was far from being universally supported.
So Palmyra was defeated in July-August 272, but apparently only. Aurelian returned to Emesa to pronounce judgement on Zenobia, her counsellors, including the philosopher Longinus who would later be executed, and probably her generals Zabdas and Zabbaios. Roman propaganda likened the victory over Palmyra to one over the Sasanians by the adding the epithets Persicus Maximus and Parthicus Maximus to Aurelian’s titles; a coin type from the Balkan mint of Siscia carried the legend Victoria Partica, a theme that is also developed in the Historia Augusta.
However, no military expedition against the Sasanians had in fact taken place: Sasanian Persia had not moved to help Palmyra. Instead, during the reign of Odenathus the dynasty of the Hairanids had built its military influence in the East at the expense of Sasanian interests; both economic and territorial rivalries placed the caravan city of Palmyra in opposition to Persia for the control of the trade routes to the East.
Second campaign against Palmyra and the repression of troubles in Egypt (end of 272-autumn 273)
Aurelian headed back towards Europe in the autumn of 272, creating Marcellinus prefect of Mesopotamia and the East. He crossed the Dardanelles in October-November 272 and, on reaching European soil in Thrace or in lower Moesia, launched a campaign against the Carpi. Zosimus suggests that the emperor was en route towards Europe when he learned of the revolt at Palmyra which seems incorrect. We must follow the account given by the Historia Augusta, the only source to report the campaign against the Carpi between the two expeditions against Palmyra. The earliest inscription to include Aurelian’s title of Carpicus Maximus is a milestone found at Callatis in Moesia Inferior. Dated by his consulship and his third tribunician year, the milestone would therefore have been erected between 10 December 271 and 10 December 272. Moreover, in addition to Carpicus Maximus, the inscription honours Aurelian with the titles Particus, Gutticus (sic) and Germanicus Maximus. He received the cognomen Parthicus during the summer of 272; therefore he was Carpicus Maximus at the end of 272, still in his third tribunician year, in other words shortly before 10 December.