Ancient authors: Tacitus, Histories 1.79 (link to Latin text and full translation).
Comments: Describing incidents pertaining to the struggles for power around the so called year of four emperors (in 69 CE), Tacitus mentions an attack by the Rhoxolanians, a Sarmatian people. In the process he outlines his stereotypes concerning this people, emphasizing their ferocity in some respects but their laziness in others. Their military techniques are thought to be extremely effective when on horseback but inept when engaging in hand-to-hand combat. Tacitus also emphasizes their supposed penchant for plunder (e.g. like bandits) rather than proper warfare.
Source of the translation: Clifford H. More, Tacitus: The Histories, LCL, volume 1 (Cambridge, MA: HUP, 1931), public domain, adapted and modernized by Harland.
79 While all men’s thoughts were in this way absorbed in civil war [i.e. during the so-called year of four emperors, with Otho pitted against Vitellius at this point], there was no interest in foreign affairs. This inspired the Rhoxolanians, a descent group (gens) of Sarmatia [located between the Don and Dnieper rivers, according to the estimate of Strabo, Geography 7.3.17] who had massacred two cohorts the previous winter, to invade Moesia with great hopes. They numbered nine thousand horses, and their ferocity (ferocia) along with their success made them more intent on plundering rather than fighting. Consequently, when they were straggling and off their guard, the Third legion with some auxiliary troops suddenly attacked them. On the Roman side everything was ready for battle. The Sarmatians were scattered or in their greed for plunder had weighted themselves down with heavy burdens and, since the slippery roads deprived them of the advantage of their horses’ speed, they were cut down as if they were in fetters. For it is a strange fact that the whole courage (virtus) of the Sarmatians is, so to speak, outside themselves. No people is so lazy (ignavus) when it comes to fighting on foot, but when they attack the foe on horseback, hardly any line can resist them. On this occasion, however, the day was wet and the snow melting. They could not use their pikes or the long swords which they wield with both hands, for their horses fell and they were weighted down by their coats of mail. This armour is the defence of their princes and all the nobility: it is made of scales of iron or hard hide. Although the armour is impenetrable to blows, it nonetheless makes it difficult for the person wearing it to get up after being thrown down by the enemy’s attack. At the same time they were continually sinking deep in the soft and heavy snow. The Roman soldier with his breast-plate easily moved around, attacking the enemy with his javelin, which he threw, or with his lances. When the situation required, the Roman soldier used his short sword and cut down the helpless Sarmatians at close quarters, for Sarmatians do not use the shield for defensive purposes. Finally, the few who escaped battle hid themselves in the swamps, where they lost their lives from the cruel winter or the severity of their wounds. When the news of this reached Rome, Marcus Aponius, governor of Moesia, was given a triumphal statue. Fulvius Aurelius, Julianus Tettius, and Numisius Lupus, commanders of the legions, were presented with the decorations of a consul. For Otho was pleased and took the glory to himself, saying that he was lucky in war and had improved public affairs through his generals and his armies.