He was soon after recalled to Rome to assume the purple on the death of Augustus.  Germanicus, who had taken command of the legions on the Rhine, became conscious of discontent among the soldiers, who threatened to carry him into Rome and thrust him into the seat of empire.  But he soothed the passions of his soldiers by gifts and promises.  A road was opened from the Rhine into the German hinterland, and Germanicus led his army into the heart of a country of which he knew but little to avenge the disasters of the Varian legions.  The forest folk eluded the invading host, which now sought to return to headquarters; but ere they had completed the journey they were assailed and suffered a severe reverse.

Numerous revolts occurred among the Gaulish legions in the service of the Roman Empire in Germany.  But the stubborn and trained resistance of the Romans no less than the inexperience of the Gauls led to a cessation of hostilities.  The secret of Roman power in Rhenish territory lay in the circumstance that the two great elements of German nationality, the nobility and the priesthood, were becoming Romanized.  But a rude culture was beginning to blossom, and a desire arose among the barbarians for unity.  They wished to band themselves into a nation.

The Franks and Goths

The most dangerous enemies of Rome during the reigns of Valerian and Gallienus were the Franks, the Alemanni, and the Goths, whose action finally decided the conquest of the Rhenish provinces of Rome.  The name Frank, or Freedman, was given to a confederacy formed in A.D. 240 by the old inhabitants of the Lower Rhine and the Weser.  It consisted of the Chauci, the Cherusci, and the Chatti, and of several other tribes of greater or less renown.  The Romans foresaw the power of this formidable union and, by the presence of the Emperor himself and his son, endeavoured to stem the invasion, which threatened their suzerainty.  The Franks, fond of liberty and imbued with a passion for conquest, crossed the Rhine, in spite of its strong fortifications, and carried their devastations to the foot of the Pyrenees.  For twelve years Gallienus attempted to stem the torrent thus freed.

The Alemanni, who belonged to the Upper Rhine, between the Main and the Danube, were composed of many tribes, the most important of which was the celebrated Suevi.  This people, who had now become a permanent nation, threatened the Empire with an invasion which was checked with difficulty after they had fought their way to the gates of Rome itself.  In A.D. 271 Aurelian completely subdued the Rhenish peoples, numbers of whom were dragged in his triumph through the streets of Rome; but after his brief reign the old condition of things reasserted itself, until Probus, who assumed the purple in 276, restored peace and order by the construction of a massive wall between the Rhine and the Danube over two hundred miles in length.  The barbarians were driven beyond the river, which had hitherto served as a boundary-line, even past the Elbe and the Neckar.  Finally, however, the internecine strife in the Imperial City forced the Romans to return thence, and Rhineland was abandoned to the will of its semi-barbarian inhabitants.