Roman Limes
It seems to have been the Flavian emperors, Vespasian and Domitian, who advanced a step farther. On the other side of the Rhine and beyond these Agri Decumates the Romans began to construct a line of forts and wooden watch-towers linked by a rampart of earth, and known as the Limes Trans-Rhenanus. This frontier of Upper Germany left the Rhine between Linz and Andernach, crossed the Lahn at Ems, and then turned eastwards north of Wiesbaden (Aquæ Mattiacæ) and Frankfort. After Saalburg it runs on a north-easterly curve to Gruningen, whence it turns south, and continues for more than 100 miles through Aschaffenburg and Worth to join the Rhætian limes at Lorch. From Lorch the Rhætian limes goes eastwards to join the Danube a few miles above Regensburg. At first perhaps it was little more than a police and customs limit, but it gradually grew into a formidable barrier behind which the Roman Empire rested in a too profound security. Trajan continued it. Hadrian strengthened it with a wall and palisade. Commodus further fortified and extended it. A similar bulwark ran along the Danube.
Plate LXXIV. DETAIL OF THE ANTONINE COLUMN
This policy of setting up immobile defences like the Great Wall of China is always a dangerous one. Useful at first and visibly strong, it tends to lull the defenders into a false security. The camps and forts grew into towns, the armies into peaceful citizens living with their wives and children and devoting themselves to trade and husbandry. Meanwhile the barbarians on the other side were growing stronger and learning the art of war as fast as the Romans were forgetting it.
After this the danger-point for the Empire shifted gradually eastwards down the Danube. Claudius had converted Thrace from an allied kingdom into a Roman province in A.D. 46. Much difficulty was caused by the Dacians, who lived just across the Danube on the north bank opposite the Roman province of Mœsia and in the modern Roumania. As the Danube was apt to become frozen in winter it ceased to offer a satisfactory frontier, so long as there were powerful enemies on the other side. At first the Romans tried the system of transplanting them, 50,000 under Augustus and 100,000 under Nero, and settling them in the province of Mœsia. But it was a stupid policy, for it meant constant intrigues between the free barbarians and their enslaved kinsfolk. Vespasian accordingly moved two legions down from Dalmatia to reinforce the two already stationed in Mœsia. But presently there arose an able and heroic king called Decebalus, who welded the Dacians into a compact and organised kingdom, and began to menace the security of the Empire. Like Marbod of Bohemia, he drilled his barbarians on the Roman model. In A.D. 85 he invaded Mœsia, won victories and did great damage. Domitian, called upon to face this peril, was content with inflicting a single defeat upon them and then accepting Decebalus as a client prince. He gave him Roman engineers and artillerymen, and even sent gifts of money which the barbarians were pleased to regard as tribute. This has been set down as cowardice, but it was certainly unwisdom in Domitian, for Decebalus grew stronger and more dangerous. It was left for Trajan, the greatest soldier of all the early emperors, to face this thorny problem in the two great Dacian Wars of 101 and 105 B.C. The whole war is depicted for us by pictures in stone. The spiral reliefs which cover the column of Trajan tell us, with far more detail than the narrative of Dio, the history of the two Dacian Wars. We see the embarkation of the Roman army, we see it on the march with its scouts in advance, we see the solemn purifications, sacrifices, and harangues which preceded battle. We see the battles themselves, in which the Romans with sword and pilum defeat the Dacians and their mail-clad Sarmatian cavalry. The great bridge built across the Danube at Viminacium by the Greek architect Apollodorus is faithfully depicted. We can watch the siege of the Dacian capital, Sarmizegethusa, and observe the construction of the siege-engines. Scenes of pathos are most graphically portrayed, the torturing of Roman prisoners by the barbarian women, the suicide of the Dacian chiefs by poison, and the death of the heroic Decebalus. At intervals throughout the story there appears and reappears the calm and stately figure of Trajan, steering his ship, sacrificing for victory, leading the march or the charge, haranguing his troops, directing the labour of engineering, consulting with his officers, or receiving the submission of the foe.[65]