# Odaenathus' Sasanian Campaigns

The Sasanian campaigns of Odaenathus (261–266 AD) constituted yet another success of the Roman armies or rather, in this specific case the Roman–Palmyrene armies, over the armies of the Sassanids for the supremacy of the nearby Kingdom of Armenia and northern Mesopotamia.

## Historical context
### Prelude

From 260 until approximately 274, the Roman Empire suffered the secession of two large territorial areas, which however allowed its survival. In the west, the usurpers of the Gallic Empire, such as Postumus (260–268), Laelian (268), Marcus Aurelius Marius (268–269), Victorinus (269–271), Domitian II (271) and Tetricus I (271–274), managed to defend the borders of the provinces of Britannia, Gaul and Hiberia. Eutropius writes:
   Gallienus having thus abandoned the state, the Roman Empire was saved in the West by Postumus and in the East by Odaenathus. (translated from Latin).
Postumus had in fact succeeded in establishing an empire in the West, centred on the provinces of Germania Inferior and Gallia Belgica which were joined shortly after by all the other Gallic and British provinces, Hispanic and, for a short time, also that of Raetia.
These emperors not only formed their own Senate at their major centre of Treveri and awarded the classical titles of consul, Pontifex maximus or tribune of the plebs to their magistrates in the name of Roma aeterna, but they also assumed the normal imperial title, minting coins at the mint of Lugdunum, aspiring to unity with Rome and, more importantly, never thinking of marching against the so-called "legitimate" emperors (such as Gallienus, Claudius Gothicus, Quintillus or Aurelian), who reigned over Rome (i.e. those who governed Italy, the western African provinces up to Tripolitania, the Danubian provinces and the Balkan area). They, on the contrary, felt they had to defend the Rhine borders and the Gallic coast from the attacks of the germanic populations of Franks, Saxons and Alemanni. The Imperium Galliarum was therefore one of the three territorial areas that allowed Rome to retain its western part.
In the East, however, it was the Kingdom of Palmyra that took over from Rome the government of the provinces of Asia minor, of Syria and Egypt, defending them from the attacks of the Persians, first with Odaenathus (261–267), appointed by Gallienus "Corrector orientis" in 264 (?),) and then with his secessionist widow, Zenobia (267–271).

### Casus belli

Faced with Shapur I's third campaign, the Roman emperor Valerian marched against the Persian monarch but was defeated near Edessa in late spring 260 and taken prisoner. The Persian emperor then ravaged Cappadocia and Cilicia, and claimed to have captured Antioch on the Orontes and Caesarea Cappadocia after a strenuous defense. However, there is no proof that Shapur I entered the central areas of northern Syria; he seems to have moved directly west into Cilicia. Taking advantage of the situation, Fulvius Macrianus, the commander of the imperial treasury, declared his sons Quietus and Macrianus Minor as joint emperors in August 260, in opposition to Valerian's son Gallienus. At first Fulvius Macrianus showed loyalty to Gallienus. Fulvius Macrianus took Antioch on the Orontes as his center and organized the resistance against Shapur I; he dispatched Balista, his praetorian prefect, to Anatolia. Shapur I was defeated in the region of Sebaste at Pompeiopolis, prompting the Persians to evacuate Cilicia while Balista returned to Antioch on the Orontes. Balista's victory was only partial: Shapur I withdrew east of Cilicia, which Persian units continued to occupy. A Persian force took advantage of Balista's return to Syria and headed further west into Anatolia. According to the Historia Augusta, Odaenathus was declared king of Palmyra as soon as the news of the Roman defeat at Edessa reached the city. It is not known if Odaenathus contacted Fulvius Macrianus and there is no evidence that he took orders from him.

## Forces in the field
### Odaenathus's army

Odaenathus assembled the Palmyrene army and Syrian peasants, then marched north to meet the Persian emperor, who was returning to Persia. Zosimus wrote that Odaenathus's army, with which he fought Shapur I in 260, probably aiding the Romans during the Battle of Edessa, included his own Palmyrene troops and remnants of Valerian's Roman legions. No evidence exists for Roman units in his ranks, but it is possible, considering that he was fighting in the vicinity of Roman legionary bases. Troops based there might have been loyal to Gallienus and thus have chosen to join Odaenathus.
The peasant element in the army was mentioned in the writings of later historians, such as the fourth century writers Festus and Orosius; the latter called the army of Odaenathus "manus agrestis syrorum", leading the historian Edward Gibbon to portray Odaenathus' troops as a "scratch army of peasants". The historian Richard Stoneman rejected Gibbon's conclusion, arguing that the success of the Palmyrenes against Shapur I and the victories achieved by Zenobia following her husband's death, which brought Syria, Egypt and Anatolia under Palmyrene authority, can hardly be described an ill-equipped, untrained peasant army. It is more logical to interpret agrestis as denoting troops from outside the urban centres, and thus, it can be concluded that Odaenathus levied his cavalrymen from the regions surrounding Palmyra where horses were normally bred and kept.

### Parthian army

The Parthian forces that took part in Odaenathus's campaigns in Persia are unknown.

## Couse of the campaign
### 260–263 (or 264): first campaign

Initially Odenathus tried to form an alliance with the Persian ruler Shapur I, but when his gifts were scornfully rejected by the latter, Odaenathus understood that his only option was to embrace the cause of Rome against the Persians. The state of neutrality that had made the fortune of the Kingdom of Palmyra was changed in favor of an active military policy, which quickly led to its ruin, while giving fame to its ruler. For these successes Odaenathus was appointed by Gallienus "corrector totius Orientis" (with high jurisdiction over a good part of the eastern Roman provinces).

#### 260

The Roman counter-offensive led to Macrianus (procurator arcae et praepositus annonae in expeditione Persica) to gather at Samosata what remained of the Roman army in the East, while the praetorian prefect, Ballista, managed to surprise the Persians near Corycus in Cilicia and push them back as far as the Euphrates. With this victory, he also pushed Shapur away from Roman Syria, re-enstablishing it once again after the disastrous defeat of Edessa in 260.
After the rejection of Odaenathus's gifts to Shapur, he set out in pursuit of the Persians, returning home from their sack of Antigonia, and before they could cross the river Euphrates he inflicted a heavy defeat on them. Following these events Gallienus appointed him "dux orientis'.

#### 261

When two usurpers, the military tribune Titus Fulvius Junius Quietus and his brother Macrianus Minor, claimed the throne of the Roman Empire that year, Odaenathus sided with Gallienus, son of the late emperor Valerian. He in fact attacked and executed the usurper Quietus to Emesa. The enterprise was appreciated by Gallienus to the point of conferring upon him the titles of "imperator" and "dux romanorum", basically recognizing at the same time a royal authority of the prince of Palmyra over the province of Syria. Odaenathus then ordered a strong levy within the ranks of his army, to restore its strength in view of an imminent Roman-Palmyrene offensive in Persian territory. However, while Quietus and Balista were in Emesa, the inhabitants killed Quietus as Odaenathus approached the city, while Balista was captured and executed by the King in autumn 261.

#### 262

Odenathus, having just completed the levy, then gathered a large army, crossed the Euphrates (probably near Samosata or Zeugma) and after fierce fighting occupied Nisibis (favorable to the Persians and destroyed it) and all of Roman Mesopotamia (including Edessa and Carrhae), which were captured after an offensive by Odaenathus, recovering much of the East (including probably Armenia itself) and forcing Shapur I to flee after defeating him in battle.
Then, he destroyed the Jewish city of Nehardea, 45 kilometres (28 mi) west of the Persian capital Ctesiphon, as he considered the Jews of Mesopotamia to be loyal to Shapur, with some sources claiming Odaenathus' destruction of Nehardea in 259 was in support of Valerian. By late 262 or early 263, Odaenathus stood outside the walls of the Persian capital Ctesiphon.

#### 263 (or until 264)

The exact route taken by Odaenathus from Palmyra to Ctesiphon remains uncertain; it was probably similar to the route Emperor Julian took in 363 during his campaign against Persia. If he did use this route, Odaenathus would have crossed the Euphrates at Zeugma then moved east to Edessa followed by Carrhae then Nisibis. Here, he would have descended south along the Khabur River to the Euphrates valley and then marched along the river's left bank to Nehardea. He then penetrated the Sassanian province of Asōristān and marched along the royal canal Naarmalcha towards the Tigris, where the Persian capital stood.
Once at Ctesiphon, again for the second time in all of his campaigns, Odaenathus immediately began a siege of the well-fortified winter residence of the Persian kings; severe damage was inflicted upon the surrounding areas during several battles with Persian troops.
   «When all the satraps of every region had gathered at Ctesiphon for the common defense, there were long battles with varying outcomes, so that the Roman victory was difficult to come by. And Odaenathus, whose ultimate goal was to free Valerian, he put in his best effort every day, and so this excellent general found himself in a critical situation due to the difficulties of these places, in enemy territory.» (translated from Latin).
The city held out and the logistical problems of fighting in enemy territory probably prompted the Palmyrenes to lift the siege. However, after a short clash outside the city, Odaenathus managed to defeat the opponents and this time, both sides retreated. Odaenathus headed north along the Euphrates carrying with him numerous prisoners and much booty.
The invasion resulted in the full restoration of the Roman lands which had been occupied by Shapur I since the beginning of his invasions in 252: Osroene and Mesopotamia. (Contrary to the account of the Historia Augusta, there is no proof that Odaenathus occupied Armenia. However, Dura-Europus and other Palmyrene posts south of Circesium, such as Anah, were not rebuilt. Odaenathus sent the captives to Rome, and by the end of 263 Gallienus assumed the title Persicus maximus ("the great victor in Persia") and held a triumph in Rome. At the end of the campaign, then:
   «Odaenathus did not fail to show respect towards Gallienus. In fact, he sent him the satraps he had captured, almost to allow him to insult them and exalt himself. When these were brought to Rome, Gallienus celebrated the triumph (in 264).» (translated from Latin).
Coinage of the year :
| Image | Value | Front | Back | Dates | Weight and diameter | Catalogue |
| | Antoninianus | GALLIENVS AVG, head of Gallienus with radiate crown to the right, the bust with draping and armour; | PAX FVNDATA, a trophy of arms with two Sassanid prisoners at its feet; a palm in exergue. | 264 / 265 to celebrate the Roman-Palmyrene armies of Odenathus who had managed to reach the Sassanid capital Ctesiphon. | 3.51, minted in Antioch; | RIC, Gallienus, V pt. 1, 164; RSC 73; Göbl 738b. |

### 265–266: second campaign
#### 265

The Historia Augusta accounts for:
   «Odaenathus had heavily defeated the Persians, had subjected Nisibis and Carrhae, all of Mesopotamia to Roman rule. It was in our power and finally we had reached Ctesiphon and King Shapur I had fled, the satraps captured, a great number of the enemy killed. He associated Odenathus himself with the Empire, conferring on him the title of "Augustus", and later minting a coin depicting him dragging Persian prisoners. This measure was welcomed by the Senate, the city [of Rome] and people of all ages.» (translated from Latin).

#### 266

The primary sources are silent regarding events following the first Persian campaign, but this is an indication of the peace that prevailed and that the Persians had ceased being a threat to the Roman East. The evidence for the second campaign is meager; Zosimus is the only one to mention it specifically. A passage in the thirteenth Sibylline Oracle is interpreted by Hartmann as an indication of a second offensive. With the rise of the Sassanid dynasty, Palmyrene trade caravans to the East diminished with only three recorded after 224. The last caravan returned to Palmyra in 266, and this was probably facilitated by the campaign, which probably took place in 266. The King marched directly to Ctesiphon, but he had to break off the siege and march north to face an influx of Germanic raiders attacking Anatolia.
The Romans used the designation Scythian to denote many tribes, regardless of their ethnic origin, and sometimes the term would be interchangeable with Goths. The tribes attacking Anatolia were probably the Heruli who built ships to cross the Black Sea in 267 and ravaged the coasts of Bithynia and Pontus, besieging Heraclea Pontica. According to the eighth-century historian George Syncellus, Odaenathus arrived at Anatolia with Herodianus and headed to Heraclea but the riders were already gone, having loaded their ships with booty. Many perished, perhaps in a sea battle with Odaenathus' forces, or possibly they were shipwrecked.

## Consequences

Thanks to these victorious campaigns, imperial authority in the East was restored, and Emperor Gallienus himself was able to celebrate a triumph, thanks to his "rector Orientis", Odaenathus, who shared his victories with his eldest son Hairan (Herod) and earned the honorary title of king of kings, in contrast to sasanian king Shapur I. During the consolidation of imperial power in the East, Odaenathus laid the foundations for the establishment of an independent kingdom in Palmyra from Rome. It was only after Odaenathus' assassination in 267 AD, which took place in either Anatolia or Syria, that this project came to fruition with his widow, Zenobia, which in the following years also managed to occupy Roman Egypt and part of Asia Minor. The new emperor Aurelian in 272 managed to reconquer the lost territories in the East, where the Kingdom of Palmyra of Queen Zenobia had replaced the Roman Empire to counter the power of the Sassanids.