Herodian (late second, first half third century): Greek historian, author of a History of the Roman Empire since the Death of Marcus Aurelius in which he describes the reign of Commodus (180-192), the Year of the Five Emperors (193), the age of the Severan dynasty (211-235), and the Year of the Six Emperors (238).
The translation was made by Edward C. Echols (Herodian of Antioch's History of the Roman Empire, 1961 Berkeley and Los Angeles) and was put online for the first time by Roger Pearse (Tertullian.Org). The version offered on these pages is hyperlinked and contains notes by Jona Lendering.
Battle of Issus
[3.4.1] [March 194] When he learned what had happened, Niger collected a huge army, but one unused to battle and toil, and marched out in haste. A large number of men, especially the youths of Antioch, presented themselves for service in the campaign, risking their lives for him. The enthusiasm of his army naturally encouraged Niger, but his soldiers were much inferior to the Illyrians in skill and courage.
[3.4.2] Both armies marched out to a flat, sweeping plain near a bay called Issus; there a ridge of hills forms a natural theater on this plain, and a broad beach slopes down to the sea, as if Nature had constructed a stadium for a battle.
[3.4.3] It was there, they say, that Darius fought his lastnote[In 333 BCE. This battle was actually the first in which Alexander the Great met Darius III Codomannus. The last one was at Gaugamela in 331.] and greatest battle with Alexander and was defeated and captured when the West defeated the East Even today a memorial and a monument of the victory remain: a city on the ridge, called Alexandria, and a bronze statue from which the region gets its name.
[3.4.4] The armies of Severus and Niger not only met at that historic spot but the outcome of the battle was the same. The armies pitched camp opposite each other toward evening, and spent a sleepless night, anxious and afraid. [31 March 194] With each of the generals urging his men on, the armies advanced to the attack at sunrise, fighting with savage fury, as if this were destined to be the final and decisive battle and Fortune would there choose one of them as emperor.
[3.4.5] After the battle had continued for a long time with terrible slaughter, and the rivers which flowed through the plain were pouring more blood than water into the sea, the rout of the forces of the East began. Driving Niger's battered troops before them, the Illyrians forced some of the fugitives into the sea; pursuing the rest as they rushed to the ridges, they slaughtered the fugitives, as well as a large number of men from the nearby towns and farms who had gathered to watch the battle from a safe vantage point.
[3.4.6] Mounting a good horse, Niger fled with a few companions to Antioch. There he found the survivors of the rout, weeping and wailing, mourning the loss of sons and brothers. Niger now fled from Antioch in despair. Discovered hiding in the outskirts of the city, he was beheaded by the pursuing horsemen.
[3.4.7] Such was the fate Niger suffered, and he paid the penalty he deserved for his negligence and indecision. In other respects, however, they say that he was in no way despicable either as emperor or as man. Having eliminated Niger, Severus now put to death without mercy all the man's friends, whether they had supported him by choice or by necessity. When he learned that some of Niger's soldiers had managed to escape across the Tigris River and that, fearing the emperor, they were joining forces with the barbarians there, he induced a few to return, by granting them full pardon, but the majority of the fugitives remained in that alien land.
[3.4.8] Thereafter, the battle tactics of the barbarians in those regions were much more effective against the close-quarter fighting of the Romans.note[This appears to be Herodian's explanation for the fact that Rome's eastern frontier was increasingly threatened during the third century. Unfortunately, it was during the reign of Severus that two Roman attacks on the Parthian Empire proved devastatingly successful. These attacks seriously weakened Rome's eastern enemy, and continued war during Caracalla/Macrinus weakened the Parthian kings even further. In the end, a new dynasty took power: the Sasanians, who were able to reorganize the empire, and became a deadly enemy to Rome (6.2). Herodian plays down the significance of Severus' Parthian wars, although he does mention one of the campaigns in 3.9.] Formerly, the barbarians did not use swords and spears in battle; they fought only as mounted archers. And instead of wearing full body armor, they rode in light, loose-fitting uniforms. Their method of fighting was to flee on horseback and shoot their arrows behind them.
[3.4.9] But since the Roman fugitives were all soldiers, and there were technicians among those who elected to settle permanently across the Tigris River, the barbarians learned from them both the use and the manufacture of arms.