On the death of Tacitus his brother Florianus claimed the empire as if fallen to him by inheritance, and the legions yielded him their obedience; but the army of the East obliged their general, Probus, to assume the purple, and a civil war commenced. The constitution of the European troops soon, however, began to give way under the heat of the sun of Asia; sickness spread among them, desertions became numerous, and when at Tarsus in Cilicia the army of Probus came to give them battle, they averted the contest by proclaiming Probus, and putting their emperor to death after a reign of less than three months.
Probus was another of those Illyrians who, born in a humble station, attained the empire by their merit, and honoured it by their virtues. He entered the army young, and speedily became distinguished for his courage and his probity. His merit did not escape the discerning eye of Valerian, who made him a tribune, though under the usual age; gave him the command of a body of auxiliary troops, and recommended him strongly to Gallienus, by whom and by the succeeding emperors he was greatly esteemed, and trusted with important commands. Aurelian rated him very highly, and is even thought to have destined him for his successor.
After the death of Florianus, Probus wrote to the senate, apologising for having accepted the empire from the hands of the soldiery, but assuring them that he would submit himself to their pleasure. A decree was unanimously passed investing him with all the imperial titles and powers. In return Probus continued to the senate the right of hearing appeals, appointing magistrates, and of giving force to his edicts by their decrees.
Tacitus had punished severely some of those concerned in the murder of Aurelian; Probus sought out and punished the remainder, but with less rigour. He exhibited no enmity toward those who had supported Florianus.
The Germans had taken advantage of the interregnum which succeeded the death of Aurelian to make a formidable irruption into Gaul, where they made themselves masters of not less than seventy cities, and were in possession of nearly the whole of the country. Probus, however, as soon as his affairs permitted (277), entered Gaul at the head of a numerous and well-appointed army. He gave the Germans several defeats, and forced them to repass the Rhine with a loss, it is said, of four hundred thousand men.[50] He pursued them over that river, and nine of their kings were obliged to come in person to sue for peace. The terms which the emperor imposed were the restoration of all their booty, the annual delivery of a large quantity of corn and cattle, and sixteen thousand men to recruit the Roman armies. These Probus distributed in parties of fifty and sixty throughout the legions, for it was his wise maxim that the aid derived from the barbarians should be felt, not seen. He also placed colonies of the Germans and other tribes in Britain, and some of the other provinces. He had further, it is said, conceived the idea of making the conquered Germans renounce the use of arms and trust for their defence to those of the Romans; but on considering the number of troops it would require he gave it up, contenting himself with making them retire behind the Nicer (Neckar) and Albis (Elbe), with building forts and towns in the country between these rivers and the Rhine, and running a wall two hundred miles in length from the Rhine to the Danube as a defence to Italy and the provinces against the Alamanni.
[278-281 A.D.]
After the conquest of the Germans the emperor led his troops into Rætia and Illyricum, where the terror of his name and his arms daunted the Goths and Sarmatians, and gave security to the provinces. He then (279) passed over to Asia, subdued the brigands of Isauria, expelled them from their fastnesses in the mountains, in which he settled some of his veterans, under the condition that they should send their sons when eighteen years of age to the army, in order that they might not be induced by the natural advantages of the country to take to a life of freebooting, and prove as dangerous as their predecessors. Proceeding through Syria he entered Egypt and reduced the people named Blemyes,[51] who had taken the cities of Coptos and Ptolemais. He concluded a peace with the king of Persia, and on his return through Thrace he bestowed lands on a body of two hundred thousand Bastarnæ, and on some of the Gepidæ, Vandals, and other tribes. He triumphed for the Germans and Blemyes on his return to Rome.
A prince so just and upright, and at the same time so warlike as Probus, might have been expected to have no competitors for empire; yet even he had to take the field against rival emperors. The first of these was Saturninus, whom he himself had made general of the East, a man of both talent and virtue, and for whom he had a most cordial esteem. But the light-minded and turbulent people of Alexandria, on occasion of his entry into their city, saluted him augustus; and though he rejected the title and retired to Palestine, he yet, not reflecting on the generous nature of Probus, deemed that he could no longer live in a private station. He therefore assumed the purple, saying with tears to his friends that the republic had lost a useful man, and that his own ruin and that of many others was inevitable. Probus tried in vain to induce him to trust to his clemency. A part of his troops joined those sent against him by the emperor; he was besieged in the castle of Apamea, and taken and slain.
After the defeat of Saturninus, two officers, named Proculus and Bonosus, assumed the purple in Germany. They were both men of ability, and the emperor found it necessary to take the field against them in person. Proculus being defeated fled for succour to the Franks, by whom he was betrayed, and he fell in battle against the imperial troops. Bonosus held out for some time, but having received a decisive overthrow, he hanged himself. As he had been remarkable for his drinking powers, one who saw him hanging cried, “There hangs a jar, not a man.” Probus treated the families of both with great humanity.[c]