Gallienus (Latin: Publius Licinius Egnatius Gallienus Augustus; c. 218 – 268) was Roman Emperor with his father Valerian from 253 to 260 and alone from 260 to 268. He ruled during the Crisis of the Third Century that nearly caused the collapse of the empire. While he won a number of military victories, he was unable to prevent the secession of important provinces.
Life

Rise to power

The exact birth date of Gallienus is unknown. The Greek chronicler John Malalas and the Epitome de Caesaribus report that he was about 50 years old at the time of his death, meaning he was born around 218. He was the son of emperor Valerian and Mariniana , who may have been of senatorial rank, possibly the daughter of Egnatius Victor Marinianus , and his brother was Valerianus Minor . Inscriptions on coins connect him with Falerii in Etruria , which may have been his birthplace; it has yielded many inscriptions relating to his mother's family, the Egnatii.^[3] Gallienus married Cornelia Salonina about ten years before his accession to the throne. She was the mother of three princes: Valerian II , who died in 258; Saloninus , who was named co-emperor but was murdered in 260 by the army of general Postumus; and Marinianus , who was killed in 268, shortly after his father was assassinated.

When Valerian was proclaimed Emperor on 22 October 253, he asked the Senate to ratify the elevation of Gallienus to Caesar and Augustus . He was also designated Consul Ordinarius for 254. As Marcus Aurelius and his adopted brother Lucius Verus had done a century earlier, Gallienus and his father divided the Empire. Valerian left for the East to stem the Persian threat, and Gallienus remained in Italy to repel the Germanic tribes on the Rhine and Danube . Division of the empire had become necessary due to its sheer size and the numerous threats it faced, and it facilitated negotiations with enemies who demanded to communicate directly with the emperor.

Early reign and the revolt of Ingenuus

Gallienus spent most of his time in the provinces of the Rhine area (Germania Inferior, Germania Superior , Raetia , and Noricum ), though he almost certainly visited the Danube area and Illyricum during 253 to 258. According to Eutropius and Aurelius Victor, he was particularly energetic and successful in preventing invaders from attacking the German provinces and Gaul, despite the weakness caused by Valerian's march on Italy against Aemilianus in 253. According to numismatic evidence, he seems to have won many victories there, and a victory in Roman Dacia might also be dated to that period. Even the hostile Latin tradition attributes success to him at this time.

In 255 or 257, Gallienus was made Consul again, suggesting that he briefly visited Rome on those occasions, although no record survives. During his Danube sojourn (Drinkwater suggests in 255 or 256), he proclaimed his elder son Valerian II Caesar and thus official heir to himself and Valerian I; the boy probably joined Gallienus on campaign at that time, and when Gallienus moved west to the Rhine provinces in 257, he remained behind on the Danube as the personification of Imperial authority.

Sometime between 258 and 260 (the exact date is unclear), while Valerian was distracted with the ongoing invasion of Shapur in the East, and Gallienus was preoccupied with his problems in the West, Ingenuus , governor of at least one of the Pannonian provinces, took advantage and declared himself emperor. Valerian II had apparently died on the Danube, most likely in 258. Ingenuus may have been responsible for that calamity. Alternatively, the defeat and capture of Valerian at the battle of Edessa may have been the trigger for the subsequent revolts of Ingenuus, Regalianus , and Postumus .^[12] In any case, Gallienus reacted with great speed. He left his son Saloninus as Caesar at Cologne , under the supervision of Albanus (or Silvanus) and the military leadership of Postumus. He then hastily crossed the Balkans , taking with him the new cavalry corps (comitatus) under the command of Aureolus and defeated Ingenuus at Mursa or Sirmium .The victory must be attributed mainly to the cavalry and its brilliant commander. Ingenuus was killed by his own guards or committed suicide by drowning himself after the fall of his capital, Sirmium.

Invasion of the Alamanni

A major invasion by the Alemanni and other Germanic tribes occurred between 258 and 260 (it is hard to fix the precise date of these events),probably due to the vacuum left by the withdrawal of troops supporting Gallienus in the campaign against Ingenuus. Franks broke through the lower Rhine, invading Gaul, some reaching as far as southern Spain, sacking Tarraco (modern Tarragona ).The Alamanni invaded, probably through Agri Decumates (an area between the upper Rhine and the upper Danube), likely followed by the Juthungi . After devastating Germania Superior and Raetia (parts of southern France and Switzerland ), they entered Italy, the first invasion of the Italian peninsula, aside from its most remote northern regions, since Hannibal 500 years before. When invaders reached the outskirts of Rome, they were repelled by an improvised army assembled by the Senate, consisting of local troops (probably prǣtorian guards) and the strongest of the civilian population.On their retreat through northern Italy, they were intercepted and defeated in the battle of Mediolanum (near present day Milan ) by Gallienus' army, which had advanced from Gaul, or from the Balkans after dealing with the Franks.The battle of Mediolanum was decisive, and the Alamanni didn't bother the empire for the next ten years. The Juthungi managed to cross the Alps with their valuables and captives from Italy. An historian in the 19th century suggested that the initiative of the Senate gave rise to jealousy and suspicion by Gallienus, thus contributing to his exclusion of senators from military commands.

The revolt of Regalianus

Around the same time, Regalianus , a military commander of Illyricum , was proclaimed Emperor. The reasons for this are unclear, and the Historia Augusta (almost the sole resource for these events) does not provide a credible story. It is possible the seizure can be attributed to the discontent of the civilian and military provincials, who felt the defense of the province was being neglected.

Regalianus held power for some six months and issued coins bearing his image. After some success against the Sarmatians , his revolt was put down by the invasion of Roxolani into Pannonia , and Regalianus himself was killed when the invaders took the city of Sirmium . There is a suggestion that Gallienus invited Roxolani to attack Regalianus, but other historians dismiss the accusation.^[25] It is also suggested that the invasion was finally checked by Gallienus near Verona and that he directed the restoration of the province, probably in person.

Capture of Valerian, revolt of Macrianus

In the East, Valerian was confronted with serious troubles. A band of Scythians set a naval raid against Pontus , in the northern part of modern Turkey. After ravaging the province, they moved south into Cappadocia . Valerian led troops to intercept them but failed, perhaps because of a plague that gravely weakened his army, as well as the contemporary invasion of northern Mesopotamia by Shapur I , ruler of the Sassanid Empire .

In 259 or 260, the Roman army was defeated in the Battle of Edessa , and Valerian was taken prisoner. Shapur's army raided Cilicia and Cappadocia (in present day Turkey ), sacking, as Shapur's inscriptions claim, 36 cities. It took a rally by an officer Callistus (Balista), a fiscal official named Fulvius Macrianus , the remains of the Eastern Roman legions, and Odenathus and his Palmyrene horsemen to turn the tide against Shapur. The Persians were driven back, but Macrianus proclaimed his two sons Quietus and Macrianus (sometimes misspelled Macrinus) as emperors. Coins struck for them in major cities of the East indicate acknowledgement of the usurpation. The two Macriani left Quietus, Ballista, and, presumably, Odenathus to deal with the Persians while they invaded Europe with an army of 30,000 men, according to the Historia Augusta. At first they met no opposition. The Pannonian legions joined the invaders, being resentful of the absence of Gallienus. He sent his successful commander Aureolus against the rebels, however, and the decisive battle was fought in the spring or early summer of 261, most likely in Illyricum, although Zonaras locates it in Pannonia. In any case, the army of the usurpers surrendered, and their two leaders were killed.

In the aftermath of the battle, the rebellion of Postumus had already started, so Gallienus had no time to deal with the rest of the usurpers, namely Balista and Quietus. He came to an agreement with Odenathus, who had just returned from his victorious Persian expedition. Odenathus received the title of dux Romanorum and besieged the usurpers, who were based at Emesa . Eventually, the people of Emesa killed Quietus, and Odenathus arrested and executed Balista about November 261.

The revolt of Postumus

After the defeat at Edessa, Gallienus lost control over the provinces of Britain, Spain, parts of Germania, and a large part of Gaul when another general, Postumus , declared his own realm (usually known today as the Gallic Empire ). The revolt partially coincided with that of Macrianus in the East. Gallienus had installed his son Saloninus and his guardian, Silvanus , in Cologne in 258. Postumus, a general in command of troops on the banks of the Rhine, defeated some raiders and took possession of their spoils. Instead of returning it to the original owners, he preferred to distribute it amongst his soldiers. When news of this reached Silvanus, he demanded the spoils be sent to him. Postumus made a show of submission, but his soldiers mutinied and proclaimed him Emperor. Under his command, they besieged Cologne, and after some weeks the defenders of the city opened the gates and handed Saloninus and Silvanus to Postumus, who had them killed. The dating of these events is not accurate, but they apparently occurred just before the end of 260. Postumus claimed the consulship for himself and one of his associates, Honoratianus, but according to D.S. Potter, he never tried to unseat Gallienus or invade Italy.

Upon receiving news of the murder of his son, Gallienus began gathering forces to face Postumus. The invasion of the Macriani forced him to dispatch Aureolus with a large force to oppose them, however, leaving him with insufficient troops to battle Postumus. After some initial defeats, the army of Aureolus, having defeated the Macriani, rejoined him, and Postumus was expelled. Aureolus was entrusted with the pursuit and deliberately allowed Postumus to escape and gather new forces. Gallienus returned in 263 or 265 and surrounded Postumus in an unnamed Gallic city. During the siege, Gallenus was severely wounded by an arrow and had to leave the field. The standstill persisted until the death of Gallienus, and the Gallic Empire remained independent until 274.

The revolt of Aemilianus

In 262, the mint in Alexandria started to again issue coins for Gallienus, demonstrating that Egypt had returned to his control after suppressing the revolt of the Macriani. In spring of 262, the city was wrenched by civil unrest as a result of a new revolt. The rebel this time was the prefect of Egypt, Lucius Mussius Aemilianus , who had already given support to the revolt of the Macriani. The correspondence of bishop Dionysius of Alexandria provides a colourful commentary on the sombre background of invasion, civil war, plague, and famine that characterized this age.

Knowing he could not afford to lose control of the vital Egyptian granaries, Gallienus sent his general Theodotus against Aemilianus, probably by a naval expedition. The decisive battle probably took place near Thebes, and the result was a clear defeat of Aemilianus. In the aftermath, Gallienus became Consul three more times in 262, 264, and 266.

Herulian invasions, revolt of Aureolus, conspiracy and death

In the years 267–269, Goths and other barbarians invaded the empire in great numbers. Sources are extremely confused on the dating of these invasions, the participants, and their targets. Modern historians are not even able to discern with certainty whether there were two or more of these invasions or a single prolonged one. It seems that, at first, a major naval expedition was led by the Heruli starting from north of the Black Sea and leading in the ravaging of many cities of Greece (among them, Athens and Sparta ). Then another, even more numerous army of invaders started a second naval invasion of the empire. The Romans defeated the barbarians on sea first. Gallienus' army then won a battle in Thrace , and the Emperor pursued the invaders. According to some historians, he was the leader of the army who won the great Battle of Naissus , while the majority believes that the victory must be attributed to his successor, Claudius II .

In 268, at some time before or soon after the battle of Naissus, the authority of Gallienus was challenged by Aureolus , commander of the cavalry stationed in Mediolanum (Milan), who was supposed to keep an eye on Postumus . Instead, he acted as deputy to Postumus until the very last days of his revolt, when he seems to have claimed the throne for himself. The decisive battle took place at what is now Pontirolo Nuovo near Milan; Aureolus was clearly defeated and driven back to Milan. Gallienus laid siege to the city but was murdered during the siege. There are differing accounts of the murder, but the sources agree that most of Gallienus' officials wanted him dead.^[44] According to the Historia Augusta , an unreliable source compiled long after the events it describes, a conspiracy was led by the commander of the guard Aurelius Heraclianus and Marcianus.

Cecropius, commander of the Dalmatians, spread the word that the forces of Aureolus were leaving the city, and Gallienus left his tent without his bodyguard, only to be struck down by Cecropius.One version has Claudius selected as Emperor by the conspirators, another chosen by Gallienus on his death bed; the Historia Augusta was concerned to substantiate the descent of the Constantinian dynasty from Claudius, and this may explain its accounts, which do not involve Claudius in the murder. The other sources (Zosimus i.40 and Zonaras xii.25) report that the conspiracy was organized by Heraclianus, Claudius, and Aurelian .

According to Aurelius Victor and Zonaras, on hearing the news that Gallienus was dead, the Senate in Rome ordered the execution of his family (including his brother Valerianus and son Marinianus) and their supporters, just before receiving a message from Claudius to spare their lives and deify his predecessor.

 

Arch of Gallienus in Rome, 262 – dedicated to, rather than built by, Gallienus.

Legacy

Gallienus was not treated favorably by ancient historians, partly due to the secession of Gaul and Palmyra and his inability to win them back. According to modern scholar Pat Southern, some historians now see him in a more positive light.Gallienus produced some useful reforms. He contributed to military history as the first to commission primarily cavalry units, the Comitatenses , that could be dispatched anywhere in the Empire in short order. This reform arguably created a precedent for the future emperors Diocletian and Constantine I .

The biographer Aurelius Victor reports that Gallienus forbade senators from becoming military commanders. This policy undermined senatorial power, as more reliable equestrian commanders rose to prominence. In Southern's view, these reforms and the decline in senatorial influence not only helped Aurelian to salvage the Empire, but they also make Gallienus one of the emperors most responsible for the creation of the Dominate , along with Septimius Severus , Diocletian, and Constantine I.

By portraying himself with the attributes of the gods on his coinage, Gallienus began the final separation of the Emperor from his subjects.A late bust of Gallienus (see above) depicts him with a largely blank face, gazing heavenward, as seen on the famous stone head of Constantine I . One of the last rulers of Rome to be theoretically called "Princeps", or First Citizen, Gallienus' shrewd self-promotion assisted in paving the way for those who would be addressed with the words "Dominus et Deus" (Lord and God).

Publius Licinius Cornelius Valerianus (died 258), also known as Valerian II, was the eldest son of Roman Emperor Gallienus and Augusta Cornelia Salonina who was of Greek origin and grandson of the Emperor Valerian who was of a noble and traditional senatorial family.

Shortly after his acclamation as Emperor (Augustus) Valerian made Gallienus his co-Emperor and his grandson, Valerian, Caesar, in 256. (For a discussion of the dynastic politics that motivated this process, see the related article on Saloninus).

The young Caesar was then established in Sirmium to represent the Licinius family in the government of the troubled Illyrian provinces while Gallienus transferred his attentions to Germany to deal with barbarian incursions into Gaul. Because of his youth (he was probably no more than fifteen at the time), Valerian was put under the guardianship of Ingenuus, who seems to have held an extraordinary command as governor of the Illyrian provinces, i.e. Upper and Lower Pannonia and Upper and Lower Moesia.

It is reported that Salonina was not happy with this arrangement. Although she could not publicly dispute the decisions of Valerian, the pater patriae which had been formally agreed by her husband, Gallienus, she suspected Ingenuus's motives and asked an officer called Valentinus, otherwise unknown, to keep an eye on him. Despite this precaution, Valerian died in early 258 in circumstances sufficiently suspicious for Gallienus to attempt to demote Ingenuus. It was this action that sparked the attempted usurpation of the Empire by Ingenuus, who had widespread support among the Illyrian garrisons and the provincial establishment.

As in case of his brother, Saloninus, who was later made Caesar in Gaul, the little we know of Valerian's short reign in Illyria is indicative of the chaotic situation that prevailed on the northern frontiers of the Empire under Valerian and Gallienus. It seems to show that the mere presence of a member of the Imperial House in a troubled region was not sufficient to assuage local fears of being neglected by the distant Emperor. The local Caesar had to wield undisputed authority in his region and command the resources and the experience to deal with the internal and external threats to its security. Diocletian and Maximian seem to have understood this when they set up Constantius Chlorus and Galerius as Caesars in Gaul and Illyria respectively some thirty-five years later.