The withdrawal of Roman legions in 194…

The first urban settlement on the grounds of what today is the center of Cologne was Oppidum Ubiorum, which was founded in 38 BCE by the Ubii, a Cisrhenian Germanic tribe.

The Romans, in them mid-forties CE, establish a small, fortified frontier town called Colonia Agrippina (modern Cologne, or Köln) located on the west bank of the Rhine in northwestern Germany.

The early career of Gnaeus Domitius Corbulo is unknown, but he was consul in 39 during the reign of Caligula, his brother-in-law through Caligula's marriage to Corbulo's half-sister Milonia Caesonia.

After Caligula's assassination, Corbulo's career had come stalled until, in 47, the new Emperor Claudius makes him commander of the Germania Inferior armies, with base camp in Colonia Agrippina.

The new assignment is a difficult one and Corbulo has to deal with major rebellions and violence outbreaks coming from Cherusci and Chauci Germanic tribes.

During his stay in Germania, the general orders the construction of a canal between the rivers Rhine and Meuse.

Parts of this engineering work, known as Fossa Corbulonis or Corbulo's Canal, have been found at archaeological digs.

Its course is about identical to the Vliet, which connects the modern towns of Leiden (ancient Matilo) and Voorburg (Forum Hadriani).

Aulus Vitellius, consul in 48, and Proconsul of Africa in either 60 or 61, in which capacity he is said to have acquitted himself with credit, has, to the general astonishment, been appointed legate of Germania Inferior.

Vitellius has meanwhile made himself popular with his subalterns and with the soldiers by outrageous prodigality and excessive good nature, which soon proves fatal to order and discipline.

He owes his elevation to the throne to Caecina and Fabius Valens, commanders of two legions on the Rhine.

Through these two men a military revolution is speedily accomplished; they refused to renew their vows of allegiance to Emperor Galba on January 1, 69, and early in 69 Vitellius is proclaimed emperor at Cologne.

More accurately, he is proclaimed Emperor of the armies of Germania Inferior and Superior.

The armies of Gaul, Brittania and Raetia side with them shortly afterwards.

By the time that they march on Rome, however, it is Otho, and not Galba, whom they have to confront.

Civilis goes to Colonia Agrippina (Cologne) after this success, and sets up camp here.

He will invest his time in the coming months persuading other tribes from northern Gaul and Germania to join the rebellion.

The rebellion in Germania is now a real threat to the Empire.

Two legions have been lost, two others (I Germanica and XVI Gallica) are controlled by the rebels.

This cannot be allowed for much longer.

Vespasian, with the Empire in his hands and the situation in Italy under control, decides to act.

He nominates Quintus Petillius Cerialis, a close relative and experienced general, as commander of the avenging force.

An enormous army is summoned to avoid the risk of a defeat.

The legions VIII Augusta, XI Claudia, XIII Gemina, XXI Rapax and the recently levied II Adiutrix are immediately sent to Germania.

Additionally, the legions I Adiutrix and VI Victrix are summoned from Hispania and XIV Gemina from Britannia.

Most parts of these legions are deployed to pacify other parts of Gaul and Germania Superior and secure the Rhine frontier.

Still, Cerialis' army is a massive one and poses a serious threat to the rebels.

Julius Tutor, one of Civilis' allies, surrenders on the news of the approaching army.

The "imprisoned" legions, I Germanica and XVI Gallica, capitulate.

They are disgraced and no longer have the confidence of Rome.

The I Germanica is disbanded and its legionaries are added to the VII Gemina in Pannonia.

XVI Gallica is reconstituted with the name of Legio XVI Flavia Firma.

Cerealis, pushing down from all directions, forces the rebels and their (now scarce) allies to retreat to the North.

The rebellion is now confined to Germania Inferior.

The revolt is quickly suppressed, but exaggerated reports of disaster had prompted Mucianus, Vespasian’s second-in-command, to depart the capital with reinforcements of his own.

Domitian, the new emperor’s younger son, eagerly seeks the opportunity to attain military glory and joins the other officers with the intention of commanding a legion of his own.

Mucianus according to Tacitus was not keen on this prospect but as he considered Domitian a liability in any capacity that is entrusted to him, he preferred to keep him close at hand rather than in Rome.

Mucianus, on the arrival of news of of Cerialis' victory over Civilis, tactfully dissuades Domitian from pursuing further military endeavors.

Domitian then writes to Cerialis personally, suggesting he hand over command of his army but is once again snubbed.

Valerian and Gallienus, too busy to protect the Gauls against the Franks and the Alamanni and the East against the Persians, have had also to tolerate the formation of the Gallic empire under the praetorian prefect Marcus Cassianius Latinius Postumus.

Postumus and another general, Silvanus, praetorian prefect and former co-director of Roman policy on Gaul (along with Postumus), had remained in Colonia (modern Köln, or Cologne) with Gallienus' sixteen-year-old son Publius Licinius Cornelius Saloninus, newly appointed caesar, after the emperor left the Rhine River for the Danube about 258.

Silvanus in summer 260  amid the chaos of an invasion by the Alamanni and Franks, demands that all booty be handed back to the treasury and its original owners.

The legions, reluctant to submit to these orders, proclaim Postumus emperor.

Postumus now besieges and attacks Cologne, where Silvanus has sided with Saloninus.

The troops loyal to Saloninus elevate him to the rank of Augustus, but Postumus, after breaching the walls of the city, has Silvanus and Saloninus killed; later he will erect a triumphal arch to celebrate his victory.

The Gauls, reeling under devastating barbarian raids and incensed at the ineffective defense mounted by their Roman emperors, support the creation of the rival Gallic empire under Postumus, who, recognized as emperor in Gaul, Spain, Germany, and Britain, sets up the capital of his empire at Cologne, complete with its own senate, consuls and praetorian guard.

Postumus represents himself as the restorer of Gaul on some of his coins, a title he earns after successfully defending Gaul against the Germans.

The coins issued by Postumus are of better workmanship and higher precious metal content than coins issued by Gallienus, who in 263 launches a campaign to defeat him, but, after initial success against the usurper, is seriously wounded and must thus return home.

Manius Acilius Aureolus, a Roman cavalry commander under Gallienus, had in 261 defeated in Thrace the army of the usurpers Macrianus Major and Macrianus Minor, who had rebelled against Gallienus.

He is sent in 265, to dispose of the rebellion of Postumus but his carelessness allows the usurper to flee.

Zosimus reports that Aureolus and other two officers conspired against Gallienus, but that all of them were punished and submitted, except Aureolus, who retained his anger against the emperor.

Gallienus, after his failed attempt at defeating Postumus, is occupied with crises in the rest of his empire and will never challenge Postumus again.

Bonosus, born in Hispania of a Briton father and a Gaulish mother, had lost his father early in life but his mother had helped him to receive a good education.

He had had a distinguished military career and an excellent service record when, while he was stationed on the Rhine, the Germans had managed to burn and destroy the fleet under his command.

Fearful of the consequences, he had proclaimed himself Roman emperor at Cologne (Colonia Agrippina) jointly with Proculus.

This does not save him from Probus, who after a lengthy and protracted struggle, manages to defeat him.

Seeing no way out, Bonosus hangs himself, leaving a wife and two sons, who Probus treats with honor.

…Colonia Agrippina (Cologne, Germany).