"The limits of the Roman empire still extended from the Western Ocean to the Tigris, and from Mount Atlas to the Rhine and the Danube. To the undiscerning eye of the vulgar, Philip appeared a monarch no less powerful than Hadrian or Augustus had formerly been. The form was still the same, but the animating health and vigour were fled. The industry of the people was discouraged and exhausted by a long series of oppression. The discipline of the legions, which alone, after the extinction of every other virtue, had propped the greatness of the state, was corrupted by the ambition, or relaxed by the weakness, of the emperors. The strength of the frontiers, which had always consisted in arms rather than in fortifications, was insensibly undermined; and the fairest provinces were left exposed to the rapaciousness or ambition of the barbarians, who soon discovered the decline of the Roman empire."
"Gibbons highly-coloured perception of the moral decline which he thought had set in once the high point of Roman civilisation under the Antonine emperors in the second century AD was passed remains highly influential... While there certainly were severe problems in the third century, particularly in relation to political stability and to the working of the coinage, nearly all the individual components of the concept of 'third-century crisis' have been challenged in recent years... historians are agreed that the critical period in the third century began with the murder of Alexander Severus in AD235 and lasted until the accession of Diocletian in AD284... Modern historians have been quick to emphasise the negative aspects of the period. But it is less obvious that contemporaries saw it in those terms... We tend to be misled in judging the period by the fact that no good contemporary narrative survives for the critical middle fifty years of the third century, so that we must depend on the often fanciful and trivializing Historia Augusta, which reads rather like a gossip column in a tabloid newspaper, and once read is hard to forget."
Averil Cameron 'The Later Roman Empire' (published 1993)
"From the great secular games celebrated by Philip [In April 248, to celebrate the thousandth anniversary of the founding of Rome] to the death of the emperor Gallienus there elapsed twenty years of shame and misfortune. During that calamitous period every instant of time was marked, every province of the Roman world was afflicted by barbarous invaders and military tyrants, and the ruined empire seemed to approach the last and fatal moment of its dissolution. The confusion of the times, and the scarcity of authentic memorials, oppose equal difficulties to the historian, who attempts to preserve a clear and unbroken thread of narration. Surrounded with imperfect fragments, always concise, often obscure, and sometimes contradictory, he is reduced to collect, to compare, and to conjecture ..."
It was during this period of confusion that Britain became part of a breakaway empire - known as the:
Edward Gibbon
GALLIC EMPIRE.
"The joint government of the father and the son subsisted about seven, and the sole administration of Gallienus continued about eight, years. But the whole period was one uninterrupted series of confusion and calamity... the Roman empire was at the same time, and on every side, attacked by the blind fury of foreign invaders, and the wild ambition of domestic usurpers ... The most dangerous enemies of Rome, during the reigns of Valerian and Gallienus, were, 1. The Franks; 2. The Alemanni; 3. The Goths; and 4. The Persians. Under these general appellations we may comprehend the adventures of less considerable tribes, whose obscure and uncouth names would only serve to oppress the memory and perplex the attention of the reader."
In the late 250s, Valerian was:
"... engaged in an indecisive and prolonged war in Mesopotamia ..."
In 260, he was taken captive by the Persians. Aurelius Victor continues:
Aurelius Victor 'Liber De Caesaribus' (written c.360)
"At the same time, although he was strenuously attempting to drive the Germans out of Gaul, Licinius Gallienus hurriedly descended on Illyricum. There at Mursa [Osijek in eastern Croatia] he defeated Ingebus [actually Ingenuus], the governor of Pannonia, who had conceived a desire to be emperor after learning of Valerian's disaster ..."
In his absence, Gallienus had left his son, Saloninus, in nominal charge. Saloninus was under the guardianship of praetorian prefect Silvanus. Real control, may however, have lain in the hands of one Marcus Cassianius Latinius Postumus:
"If anyone, indeed, desires to know the merits of Postumus, he may learn Valerian's opinion concerning him from the following letter which he wrote to the Gauls: "As general in charge of the Rhine frontier and governor of Gaul we have named Postumus, a man most worthy of the stern discipline of the Gauls. He by his presence will safeguard the soldiers in the camp, civil rights in the forum, law-suits at the bar of judgement, and the dignity of the council chamber, and he will preserve for each one his own personal possessions; he is a man at whom I marvel above all others and well deserving of the office of prince, and for him, I hope you will render me thanks. If however, I have erred in my judgement concerning him, you may rest assured that nowhere in the world will a man be found who can win complete approval...""
'Historia Augusta' in the persona of Trebellius Pollio
"... inclined towards innovation, and accompanied some soldiers that revolted at the same time to Agrippina [Cologne], which is the principal city on the Rhine, in which he besieged Saloninus, the son of Gallienus, threatening to remain before the walls until he was given up to him. On this account the soldiers found it necessary to surrender both him and Silvanus, whom his father had appointed his guardian, both of whom Posthumus [sic] put to death and made himself sovereign of the Celtæ [Gauls]."
Trebellius Pollio (whose portrait of Postumus is positively glowing, whereas that of Gallienus is little short of a character assassination) refuses to associate any dishonourable conduct with Postumus:
"... some writers assert - though it does not accord with his character - he [Postumus] ... broke faith and after slaying Saloninus seized the imperial power. As others, however, have related with greater truth, the Gauls themselves, hating Gallienus most bitterly and being unwilling to endure a boy as their emperor, hailed as their ruler the man who was holding the rule in trust for another [i.e. Postumus], and despatching soldiers they slew the boy."
"... Postumus, a man of extremely insignificant family, assumed the purple in Gaul and for ten years ruled in such a way that he restored the provinces which had almost been ruined, by means of his great vigour and restrained government."
Britain, Spain, and, for a time at least, probably the province of Raetia (southwest Germany, Austria and Switzerland) were a part of this 'Gallic Empire'. Gallienus appears to have mounted a couple of campaigns against Postumus (the suggested date is 265), with mixed success, but failed to dislodge him. Gallienus apparently received an arrow wound whilst besieging Postumus in an unnamed town. In 268, however:
Eutropius 'Breviarium Ab Urbe Condita' (written 369)
"... intelligence was brought to Gallienus, who was then occupied in the Scythian war [ie against the Goths], that Aurelianus, or Aureolus, who was commander of the cavalry posted in the neighbourhood of Milan to watch the motions of Posthumus, had formed some new design, and was ambitious to be emperor. Being alarmed at this he went immediately to Italy ..."
Whilst he was campaigning against Aureolus, Gallienus was assassinated. Claudius (known as Claudius Gothicus or Claudius II) became emperor, and disposed of Aureolus. At around this time, Postumus' coinage apparently underwent a sudden debasement. There is speculation that he needed to dramatically increase the number of coins minted in order to buy the loyalty of his troops (perhaps they thought he should have taken advantage of the situation and marched into Italy). At any rate, probably in 269, Postumus had to face a rebellion:
Zosimus
"After he had driven off a horde of Germans he was involved in a war with Laelianus whom he routed just as successfully, but he then perished in a revolt of his own men supposedly since he had refused to allow them, despite their insistence, to plunder the inhabitants of Mainz because they had supported Laelianus."
Aurelius Victor
"... Marius, a totally common tradesman, received the purple and was killed the following day. Victorinus afterwards received the government of the Gauls"
The Gallic Empire began to crumble. Spain appears to have shifted its allegiance back to the legitimate empire, and Rome recovered some territory in southern Gaul. There was a rebellion at the city of Augustodorum Haedorum (Autun), which Victorinus eventually (after a siege of seven months) suppressed.
Eutropius
"Victorinus ... equalled Postumus in military expertise but was a compulsive lecher. Although he restrained himself at the beginning, he forcibly violated very many women and after a reign of two years, when he forced his attentions on the wife of Attitianus and she informed her husband of the outrage, the soldiers were secretly incited and he was killed at Cologne in a mutiny... Victoria, after the loss of her son Victorinus, bought the approval of the legions with a large sum of money and made Tetricus emperor. He was of a noble family and was serving as governor of Aquitaine, and the title and trappings of Caesar were bestowed upon his son Tetricus."
Aurelius Victor
"... Tetricus ... was chosen emperor in his absence by the soldiers and assumed the purple at Bordeaux. He endured many military revolts."
Meanwhile, in 270, Claudius Gothicus had died, and was, for a brief time (of unclear duration), succeeded by his brother Quintillus. Quintillus was killed (or committed suicide) and the purple was assumed by Aurelian. In 273, Aurelian decided that Gaul should be reunited with the Empire, and marched against Tetricus. Events took a somewhat surprising turn. Probably early in 274, at Châlons-sur-Marne:
Eutropius
"... Tetricus himself betrayed his own army since he could not endure its constant mutinies. Indeed through secret letters he so entreated Aurelian that he used, among others, the [following] verse of Vergil: "Snatch me, invincible one, from these evils.""
Eutropius
"... during the fighting he surrendered to Aurelian as he approached. So, as is usual when there is no commander, the ranks were thrown into confusion and crushed."
Tetricus was displayed, in Rome, at Aurelian's triumph, but, in a final twist, he:
Aurelius Victor
"... then obtained the governorship of Lucania [in southern Italy] and for his son pardon and senatorial rank."
Aurelian was murdered in the autumn of 275. After a short interregnum Tacitus was selected as his successor. Tacitus reigned for about seven months before he too was (probably) murdered, and Florian assumed the purple. He was immediately challenged by Probus, who, according to Zosimus:
Aurelius Victor
"... governed all Syria, Phœnicia, Palestine, and Egypt ..."
Florian, on the other hand:
"... was in possession of all the countries from Cilicia to Italy; besides which the homage of all the nations beyond the Alps, the Gauls, Spaniards, Britons, and Africans was paid to him."
The opposing factions met at Tarsus, where Florian's army was apparently overcome by the extreme heat. Only a few skirmishes were fought; Florian was killed by his own soldiers (having reigned for around two months).
Probus ruled from 276 to 282, and during this time three pretenders to his throne are chronicled (although their date is unclear, and the subject of debate): Saturninus in Syria, Proculus in Gaul, and Bonosus in Gaul. The 'Historia Augusta' (in the guise of Flavius Vopiscus of Syracuse) asserts that Proculus and Bonosus:
"... proceeded to claim all of Britain and Spain and the provinces also of Farther Gaul ..."
The rebellions were successfully suppressed, however, and Zosimus states that Probus:
"... likewise suppressed an insurrection in Britain, by means of Victorinus, a Moor, who had persuaded him to confer the government of Britain upon the leader of the insurgents. Having sent for Victorinus, and chosen him for his consul, he sent him to appease the disturbance; who going presently to Britain, took off the traitor by a stratagem."
Probus' reign appears to have been characterised by conspicuous military success:
"... Probus obtained several victories over the Barbarians in two different wars; in one of which he himself commanded, but left the other to the conduct of his lieutenant. Perceiving that it was necessary to assist the cities of Germany which lay upon the Rhine, and were harassed by the Barbarians, he marched with his army towards that river. When the war began there, a grievous famine prevailed throughout the surrounding country; but a heavy shower of rain and corn fell together, so that in some places were great heaps of it made by its own descent. At this prodigy, all were so astonished that at first they dared not touch the corn to satisfy their hunger; but being at length forced to it by necessity, which expels all fear, they made bread of it, which not only allayed their hunger, but enabled them to gain the victory with great ease."
Zosimus
"... he [Probus] set out with a huge army for the provinces of Gaul, which since the death of Postumus had all been in turmoil, and after the murder of Aurelian had been seized by the Germans. There, moreover, he fought battles so great and successful that he took back from the barbarians sixty most famous communes of Gaul ... Probus, after slaying about four hundred thousand who had seized upon Roman soil, drove all the rest back beyond the river Neckar and the district of Alba [the Swabian Alb] ..."
Flavius Vopiscus of Syracuse
"The emperor terminated several other wars, with scarcely any trouble; and fought some fierce battles, first against the Longiones, a German nation, whom he conquered ..."
Zosimus
"Opposite Roman cities, moreover, he built camps on barbarian soil and in these he stationed troops... All the while the heads of barbarians were brought in to him daily, now at the price of an aureus apiece, and he never ceased fighting until nine princes of different tribes came before him and prostrated themselves at his feet... He took besides sixteen thousand recruits, all of whom he scattered through the various provinces, incorporating bodies of fifty or sixty in the detachments or among the soldiers along the frontier; for he said that the aid that Romans received from barbarian auxiliaries must be felt but not seen."
Flavius Vopiscus of Syracuse
"Another of his battles was against the Franks, whom he subdued through the good conduct of his commanders. He made war on the Burgundi and the Vandili... All of them that were taken alive were sent to Britain, where they settled, and were subsequently very serviceable to the emperor when any insurrection broke out."
Probus' continuing success prompted Flavius Vopiscus of Syracuse to claim that he:
Zosimus
"... restored to perfect safety the east, the west, the south, and the north, indeed all parts of the world ... "
This success, however, did not make Probus immune to the fickleness of the army. In 282 he was killed by his own men, either in a simple mutiny, or as the result of a revolt by his successor, Carus. Carus soon followed the example of Valerian, and divided control of the Empire between himself (in the east) and his elder son Carinus (the west). Whilst Carus and his younger son, Numerian, were campaigning against the Persians, in 283, Carus died. Numerian became co-emperor with Carinus who, probably around this time, fought a campaign in Britain, from which both he and his brother acquired the appellation 'Britannicus Maximus'. During the following year, 284, Numerian was killed, and Diocletian was chosen as his successor. Carinus, pausing to suppress the rebellion of one Julianus at Verona, marched against Diocletian. In the summer of 285, the two armies met at a site near Belgrade. Carinus' larger army was apparently at the point of victory when he was murdered by his own men, leaving Diocletian as sole emperor.