The Battle of Naissus in 268 or 269 was the defeat of a Gothic coalition by the Roman Empire under Emperor Gallienus (or Emperor Claudius II Gothicus) and the future Emperor Aurelian near Naissus (Niš). The events around the invasion and the battle are an important part of the history of the Crisis of the Third Century.
The result was a great Roman victory which, combined with the effective pursuit of the invaders in the aftermath of the battle and the energetic efforts of the future Emperor Aurelian, largely removed the threat from Germanic tribes in the Balkan frontier for the following decades.
Background
The battle of Naissus came about as a result of two massive invasions of "Scythian" tribes (as our sources anachronistically call them) into Roman territory between 267 and 269. The first wave came during the reign of Gallienus in 267 and started when the Heruli, raiding on 500 ships, ravaged the southern Black Sea coast and unsuccessfully attacked Byzantium and Cyzicus. They were defeated by the Roman navy but managed to escape into the Aegean Sea, where they ravaged the islands of Lemnos and Skyros and sacked several cities of the southern Greek province of Achaea, including Athens, Corinth, Argos, and Sparta. Then an Athenian militia, led by the historian Dexippus, pushed the invaders to the north where they were intercepted by the Roman army under Gallienus. He won an important victory near the Nestos River, on the boundary between Macedonia and Thrace, with the aid of the Dalmatian cavalry. Reported barbarian casualties were 3,000 men. Subsequently, the Heruli leader Naulobatus came to terms with the Romans.
In the past, the battle on the Nessos was identified as the Battle of Naissus, but modern scholarship has rejected this view. On the contrary, there is a theory that the victory at Nessos was so decisive that Claudius' efforts against the Goths (including the battle of Naissus) were no more than a mopping-up operation. After his victory, Gallienus left Lucius Aurelius Marcianus in place and hastily left for Italy, intending to suppress the revolt of his cavalry officer Aureolus. After Gallienus was assassinated outside Milan in the summer of 268 in a plot led by high officers in his army, Claudius was proclaimed emperor and headed to Rome to establish his rule. Claudius' immediate concerns were with the Alemanni, who had invaded Raetia and Italy. After he defeated them in the Battle of Lake Benacus, he was finally able to take care of the invasions in the Balkan provinces.
In the meantime, the second and larger sea-borne invasion had started. An enormous coalition of "Scythians"—actually consisting of Goths (Greuthungi and Thervingi), Gepids, and Peucini, led again by the Heruli—assembled at the mouth of river Tyras (Dniester). The Augustan History and Zosimus claim a total number of 2,000–6,000 ships and 325,000 men. This is probably a gross exaggeration but remains indicative of the scale of the invasion. After failing to storm some towns on the coasts of the western Black Sea and the Danube (Tomis, Marcianopolis), the invaders attacked Byzantium and Chrysopolis. Part of their fleet was wrecked, either because of Gothic inexperience in sailing through the violent currents of the Propontis or because it was defeated by the Roman navy. They then entered the Aegean Sea and a detachment ravaged the Aegean islands as far as Crete and Rhodes. While their main force had constructed siege works and was close to taking the cities of Thessalonica and Cassandreia, it retreated to the Balkan interior at the news that the emperor was advancing. On their way, they plundered Doberus (Paionia?) and Pelagonia.
Battle
The Goths were engaged near Naissus by a Roman army advancing from the north. The battle most likely took place in 268, and was fiercely contested. Large numbers on both sides were killed but, at the critical point, the Romans tricked the Goths into an ambush by pretended flight. Some 50,000 Goths were allegedly killed or taken captive. It seems that Aurelian, who was in charge of all Roman cavalry during reign of Claudius, led the decisive attack in the battle.
Aftermath
A large number of Goths managed to escape towards Macedonia, initially defending themselves behind their laager. Soon, many of them and their pack animals, distressed as they were by the harassment of the Roman cavalry and the lack of provisions, died of hunger. The Roman army methodically pursued and surrounded the survivors at Mount Haemus where an epidemic affected the entrapped Goths. After a bloody but inconclusive battle, they escaped but were pursued again until they surrendered. Prisoners were admitted to the army or given land to cultivate and become coloni. The members of the pirate fleet, after the failed attacks on Crete and Rhodes, retreated and many of them suffered a similar end. However the plague also affected the pursuing Romans and Emperor Claudius, who died from it in 270.
The psychological impact of this victory was so strong that Claudius became known to posterity as Claudius II Gothicus Maximus ("conqueror of the Goths"). However devastating the defeat, the battle did not entirely break the military strength of the Gothic tribes. Besides, the troubles with Zenobia in the east and the breakaway Gallic Empire in the West were so urgent that the victory at Naissus could only serve as a temporary relief for the troubled Empire. In 271, after Aurelian repelled another Gothic invasion, he abandoned the province of Dacia north of the Danube in order to rationalize the defense of the Empire.