Succession of Emperors and Usurpers

The period from the death of Severus Alexander to the time of Claudius II Gothicus was marked by usurpations and barbarian invasions. After Maximinus the Thracian, who bravely fought the Alemanni but showed great hostility toward the Senate and the educated elite, the Gordians rose to power as a result of a revolt by wealthy African landowners. A senatorial reaction first imposed civilian emperors, Pupienus and Balbinus together, and then named Gordian III, a youth backed by his father-in-law, the praetorian prefect Timesitheus. Gordian III was murdered by the soldiers during a campaign against the Persians and was replaced, first by Philip the Arabian and then by Decius, both soldiers. Decius tried to restore Roman traditions and also persecuted the Christians, but he was killed by the Goths in 251 in a battle near the Black Sea. From 253 to 268 two Roman senators, Valerian and his son Gallienus, reigned. Valerian revived the persecution of the Christians, but he was captured by the Persians during a disastrous campaign and died in captivity (260; see photograph). His son then reigned alone, facing multiple invasions and several usurpations. He moved constantly between the Rhine and the Danube, achieving brilliant victories (Milan in 262, the Nestus in 267), but the Pannonian army raised several competitors against him (Ingenuus, Regalianus, Aureolus). Too busy to protect the Gauls against the Franks and the Alemanni and the East against the Persians, he had to tolerate the formation of the Gallic empire under the praetorian prefect Marcus Cassianius Postumus (259–268) and the Palmyrene kingdom of Odenathus (260–267). Some of his reforms were a foreshadowing of the future: the senators were practically excluded from the army; the equites received the majority of commands and of provincial governorships; and the composition of the army was modified by the creation of new army corps and especially of a strong cavalry, which was placed under the command of a single leader and charged with closing the breaches that the barbarians were opening along the frontiers. Upon his father’s death Gallienus had put an end to the persecution of the Christians, preferring to fight the new religion through intellectual means; to that end, he favoured the ancient Greek cults (Demeter of Eleusis) and protected the Neoplatonist philosopher Plotinus. These initiatives increased the number of his enemies, particularly among the patriotic senators and the Pannonian generals. While Gallienus was in Milan besieging the usurper Aureolus, he was killed by his chiefs of staff, who proclaimed Claudius II (268), the first of the Illyrian emperors. The new emperor won a great victory against the Alemanni on the Garda lake and overwhelmed the Goths in Naissus (269) but died of the plague in 270. This fatal period brought to light one of the major defects of the empire: the lack of a legitimate principle of succession and the preponderant role of the army in politics. The structures that had created the strength of the principate were weakened, and the empire required deep reforms. Gallienus had felt their necessity but had been too weak to impose them.

The barbarian invasions
The Goths were Germans coming from what is now Sweden and were followed by the Vandals, the Burgundians, and the Gepidae. The aftereffect of their march to the southeast, toward the Black Sea, was to push the Marcomanni, the Quadi, and the Sarmatians onto the Roman limes in Marcus Aurelius’ time. Their presence was brusquely revealed when they attacked the Greek towns on the Black Sea about 238. Timesitheus fought against them under Gordian III, and under Philip and Decius they besieged the towns of Moesia and Thrace, led by their kings, Ostrogotha and Kniva. Beginning in 253, the Crimean Goths and the Heruli appeared and dared to venture on the seas, ravaging the shores of the Black Sea and the Aegean as well as several Greek towns. In 267 Athens was taken and plundered despite a strong defense by the historian Dexippus. After the victories of Gallienus on the Nestus and Claudius at Naissus (Nish), there was for a time less danger. But the countries of the middle Danube were still under pressure by the Marcomanni, Quadi, Iazyges, Sarmatians, and the Carpi of free Dacia, who were later joined by the Roxolani and the Vandals. In spite of stubborn resistance, Dacia was gradually overwhelmed, and it was abandoned by the Roman troops, though not evacuated officially. When Valerian was captured in AD 259/260, the Pannonians were gravely threatened, and Regalianus, one of the usurpers proclaimed by the Pannonian legions, died fighting the invaders. The defense was concentrated around Sirmium and Siscia-Poetovio, the ancient fortresses that had been restored by Gallienus, and many cities were burned.

In the West the invasions were particularly violent. The Germans and the Gauls were driven back several times by the confederated Frankish tribes of the North Sea coast and by the Alemanni from the middle and upper Rhine. Gallienus fought bitterly, concentrating his defense around Mainz and Cologne, but the usurpations in Pannonia prevented him from obtaining any lasting results. In 259–260 the Alemanni came through the Agri Decumates (the territory around the Black Forest), which was now lost to the Romans. Some of the Alemanni headed for Italy across the Alpine passes; others attacked Gaul, devastating the entire eastern part of the country. Passing through the Rhône Valley, they eventually reached the Mediterranean; and some bands even continued into Spain. There they joined the Franks, many of whom had come by ship from the North Sea, after having plundered the western part of Gaul. Sailing up the estuaries of the great rivers, they had reached Spain and then, crossing the Strait of Gibraltar, had proceeded to Mauretania Tingitana. Gallienus, outflanked, entrusted Gaul and his young son Saloninus to Postumus, who then killed Saloninus and proclaimed himself emperor. The several invasions had so frightened the people that the new emperor was readily accepted, even in Spain and Britain. He devoted himself first to the defense of the country and was finally considered a legitimate emperor, having established himself as a rival to Gallienus, who had tried in vain to eliminate him but finally had to tolerate him. Postumus governed with moderation, and, in good Roman fashion, minted excellent coins. He, too, was killed by his soldiers, but he had successors who lasted until 274.

Difficulties in the East

In the East the frontiers had been fixed by Hadrian at the Euphrates. But under Nero, the Romans had claimed control over the kings of Armenia, and under Caracalla they had annexed Osroëne and Upper Mesopotamia. The Parthian empire had been weak and often troubled, but the Sāsānids were more dangerous. In 241, Shāpūr I (Sapor), an ambitious organizer and statesman, mounted the throne: he united his empire by bringing the Iranian lords into line and by protecting the Zoroastrian religion. He also tolerated the Manichaeans and put an end to the persecutions of the Christians and Jews, thereby gaining the sympathy of these communities. In 252, with a large army at his command, Shāpūr imposed Artavasdes on Armenia, attacked Mesopotamia, and took Nisibis. In 256 his advance troops entered Cappadocia and Syria and plundered Antioch, while Doura-Europus, on the middle Euphrates, was likewise falling to him. Valerian had rushed to its aid, but he could not remedy the situation; and in 259 or 260 he was imprisoned by Shāpūr during operations about which little is known. Mesopotamia was lost and Rome was pushed back to the Euphrates. Cappadocia, Cilicia, and Syria were again plundered, and a puppet emperor was appointed in Antioch. But these victories were transitory: in Osroëne, Edessa had shown resistance, a defense was organized in Cappadocia and Cilicia, and Odenathus, the prince of Palmyra, took Shāpūr by surprise and forced him back to Iran. Having thus aided the Roman cause, Odenathus then began to act in his own interest: he continued the fight against the Persians and took the title “King of Kings.” The Romans officially entrusted him with the defense of the East and conferred on him the governorship of several provinces; the “kingdom” of Palmyra thus extended from Cilicia to Arabia. He was murdered in 267 without ever having severed his ties with Gallienus. His widow Zenobia had her husband’s titles granted to their son Vaballathus. Then in 270, taking advantage of the deaths of Gallienus and Claudius II, she invaded Egypt and a part of Anatolia. This invasion was followed by a rupture with Rome, and in 271 Vaballathus was proclaimed Imperator Caesar Augustus. The latent separatism of the Eastern provinces and, undoubtedly, some commercial advantages caused them to accept Palmyrene domination without difficulty, as they had, in the past, supported Avidius Cassius and Pescennius Niger against the legitimate emperors. In 272 unity was restored by Aurelian, but Mesopotamia was lost, and the Euphrates became the new frontier of the empire.

Economic and social crisis

The invasions and the civil wars worked in combination to disrupt and weaken the empire over a span of half a century. Things were at their worst in the 260s, but the entire period from 235 to 284 brought the empire close to collapse. Many regions were laid waste (northern Gaul, Dacia, Moesia, Thrace, and numerous towns on the Aegean); many important cities had been pillaged or destroyed (Byzantium, Antioch, Olbia, Lugdunum); and northern Italy (Cisalpine Gaul) had been overrun by the Alemanni. During the crisis, the emperor either focused his forces on the defense of one point, inviting attack at another, or he left some embattled frontier altogether to its own devices; any commander who proved successful had the emperorship thrust upon him, on the very heels of his victories over the invaders. Counting several sons and brothers, more than 40 emperors thus established themselves for a reign of some sort, long or (more often) short. The political destabilization fed on itself, but it also was responsible for heavy expenditure of life and treasure. To keep pace with the latter, successive emperors rapidly and radically reduced the percentage of precious metal in the standard silver coins to almost nothing so as to spread it over larger issues. What thus became a fiduciary currency held up not too badly until the 260s, when confidence collapsed and people rushed to turn the money they had into goods of real value. An incredible inflation got under way, lasting for decades.

The severity of damage done to the empire by the political and economic destabilization is not easily estimated since for this period the sources of every sort are extremely poor. Common sense would suggest that commerce was disrupted, taxes collected more harshly and unevenly, homes and harvests destroyed, the value of savings lost to inflation, and the economy in general badly shaken. A severe plague is reported that lasted for years in mid-century, producing terrible casualties. In some western areas, archaeology provides illustration of what one might expect: cities in Gaul were walled, usually in much reduced circuits; villas here and there throughout the Rhine and Danube provinces also were walled; road systems were defended by lines of fortlets in northern Gaul and adjoining Germany; and a few areas, such as Brittany, were abandoned or relapsed into pre-Roman primitiveness. Off the coasts of that peninsula and elsewhere, too, piracy reigned; on land, brigandage occurred on a large scale. The reentrant triangle of land between the upper Danube and upper Rhine had to be permanently abandoned to the barbarians around it in about 260. The Pax Romana had then, in all these manifest ways, been seriously disrupted. On the other hand, in Egypt, where inflation is most amply documented, its harmful effects cannot be detected. The Egyptian economy showed no signs of collapse. Furthermore, some regions—most of Britain, for example—emerged from the half-century of crisis in a more prosperous condition than before. A summary of the effects of crisis can only underline one single fact that is almost self-evident: the wonders of civilization attained under the Antonines required an essentially political base. They required a strong, stable monarchy in command of a strong army. If either or both were seriously disturbed, the economy would suffer, along with the civilization’s ease and brilliance. If, on the other hand, the political base could be restored, the health of the empire as a whole was not beyond recovery.

In the meantime, certain broad changes unconnected with the political and economic crisis were going forward in the 3rd century. Civilians increasingly complained of harassment and extortion by troops stationed among them; exaction of taxes intended for the army also became the target of more frequent complaint; and demands by soldiers to interfere in civilian government, foremost by those stationed in the capital, grew more insolent. The choice of emperor became more and more openly the prerogative of the military, not the Senate; and, as mentioned, in the 260s senators were being largely displaced from high military commands. The equestrian rank, in which persons risen from military careers were often to be found, was the beneficiary of the new policy. In sum, the power of the military, high and low, was asserting itself against that of the civilians. From this change, further, there flowed certain cultural consequences; for, continuing the tendencies detectable even in the 1st century, the army was increasingly recruited from the most backward areas, above all, from the Danubian provinces. Here, too—indeed, throughout the whole northern glacis of the empire—it had been state policy to allow entire tribes of barbarians to immigrate and to settle on vacant lands, where they dwelled, farmed, paid taxes, and offered their sons to the army. Such immigrants, in increasingly large numbers from the reign of Marcus Aurelius on, produced, with the rural population, a very non-Romanized mix. From the midst of just such people, Maximinus mounted to the throne in 235, and later, likewise, Galerius (Caesar from 293). It is quite appropriate aesthetically, from Aurelian on, that these later 3rd-century rulers chose to present themselves to their subjects in their propaganda with stubbly chin, set jaw, and close-cropped hair on a bullet head