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. The recovery of the empire and the establishment of the dominate (270–337) The Illyrian emperors
After Claudius II’s unexpected death, the empire was ruled from 270 to 284 by several “Illyrian” emperors, who were good generals and who tried in an energetic way to restore equilibrium. The most remarkable was Aurelian. He first gained hard-won victories over the Alemanni and the Juthungi, who had invaded the Alpine provinces and northern Italy. To cheer the inhabitants of Rome, who had succumbed to panic, he began construction of the famous rampart known as Aurelian’s Wall. And while crossing the Danubian provinces, before marching against Palmyra, he decided on an orderly evacuation of Dacia, an undefendable region that had been occupied by the barbarians since the time of Gallienus. In the East, he defeated Zenobia’s troops easily and occupied Palmyra in 272. Shortly afterward, an uprising broke out in Egypt under the instigation of a rich merchant, who, like a great part of the population, was a partisan of the Palmyrene queen. In response, Aurelian undertook a second campaign, plundering Palmyra and subjugating Alexandria. These troubles, however, along with the devastation of the great caravan city, were to set back Roman trade seriously in the East. Later, rounding back on the Gallic empire of Postumus’ successors, he easily defeated Tetricus, a peaceful man not very willing to fight, near Cabillonum. The unity of the empire was restored, and Aurelian celebrated a splendid triumph in Rome. He also reestablished discipline in the state, sternly quelled a riot of artisans in the mints of Rome, organized the provisioning of the city by militarizing several corporations (the bakers, the pork merchants), and tried to stop the inflation by minting an antoninianus of sounder value. His religious policy was originaclass="underline" in order to strengthen the moral unity of the empire and his own power, he declared himself to be the protégé of the Sol Invictus (the Invincible Sun) and built a magnificent temple for this god with the Palmyrene spoils. Aurelian was also sometimes officially called dominus et deus: the principate had definitely been succeeded by the “dominate.” In 275 Aurelian was murdered by certain officers who mistakenly believed that their lives were in danger.