Why didn't the Romans complete their conquests of Germania and Britannia?

[PicturesquePict]

In 13 BC - 6 AD the Romans conquered all territories between the Elbe and the Rhine.

In 9 AD a Germanic tribal confederacy under the Cherusci leadership of their chieftain Arminius started an uprising against Roman occupation, and managed to destroy 3 legions under Varus in an ambush in the Teutoburg Forest, thus ending Roman rule over those lands.

But in 14 - 16 AD Nero Claudius Drusus Jr. (better known as Germanicus after his father's victories in Germania) invaded Germania with an army of 8 legions, 2 praetorian cohorts, cavalry, horse & foot archers, and other supporting trrops (Tacitus, Annals, II.16), as well as levies from Germanic tribes which remained under Roman rule on the left bank of the Rhine (Annals, I.56). His campaigns were a total success with 2 out of 3 legionary eagles lost in 9 AD recovered, bodies of the fallen buried, pregnant wife of Ariminius, Thusnelda and his father Segestes captured (I.57), several tribes massacred, and Ariminus decisively defeated (huge battles of Idistavisus and of the Angivarian Wall in 16 AD). And yet territorial expansion did not follow, and Emperor Tiberius denied the request of Germanicus to launch an additional final campaign for AD 17, having decided the frontier with Germania would stand at the Rhine river. Tacitus, with some bitterness, asserts that had Germanicus been given full independence of action, he could have completed the conquest of Germania.

A very similar situation was in Scotland, which was invaded by Gnaeus Julius Agricola in 83 - 84 AD, and the Romans won a decisive victory against the Caledonian Confederacy led by Calgacus in the battle of Mons Graupius. Yet the Romans did not annexed that land, instead deciding that the frontier would stand between the Firth of Forth and the Firth of Clyde, where they built the Antonine Wall after 142 AD. The opportunity to complete the conquest of Britannia was lost (Perdomita Britannia et statim missa - Britain was completely conquered and immediately let go, as Tacitus wrote).

So why were the Romans uninterested, or perhaps unable to, conquer those lands ???

 

[Civ1407]

Germany east of the Rhine wasn't developed enough the sustain the amount of legions needed to control this area.
It was more cost effcetive to secure the shorter Rhine-Danube Border (with less legions), which could be easily supplied bythe RHone valley, than to secoure the longer Elbe-Moldau-Danube border which needed to be supplied on an overland route or over the North Sea.

At the end it was a simple cost-benefit analysis.

I think it was the same with Northern Great Britain

 

[schlaufuchs]

Too remote with no real resources or political structures worth investing money/manpower into. The Germanii political structues could be managed and mitigated from behind the Rhine without needing to devote valuable resources and manpower to removing by force and Pictish incursions weren't frequent or concentrated enough to warrant more than a wall. Both regions were undeveloped and relatively sparsely populated. Remember the Romans did occupy Dacia but were eventually forced to abandon it.

History isn't like RTW or EU; you don't just roll in with an army, besiege a city and call the province yours. The process of conquering regions was a much more long and drawn out process entailing inserting Roman hegemony into existing structures. Convincing the local élite to align themselves with the Romans because it'll be beneficial to them to do so. You can draw all corners of Europe red if you want, but it doesn't mean a thing if the powers at the local level don't acknowledge it. The thing which truly made the Roman Empire great was that for the vast majority of its history its political players were incredibly good at doing this; at playing local cliques off one another and incentivizing cooperation with the Roman state through the bestowal of privileges and patronage which lent legitimacy to those local cliques. The larger the Empire gets the more difficult it becomes for the Emperor to properly service these various cliques. As the empire grows larger, or weakens financially/politically, or if an emperor is not suited to the task of servicing and maintaining the political structures, it becomes more difficult for the Empire to maintain existing structures at a satisfactory level and the cliques are going to look elsewhere for the patronage. As long as the name and prestige of "Romanness" is still useful then that looking elsewhere is going to remain couched within a Roman context - you're going to have civil wars, but if the benefits of aligning oneself with the prestige of the Roman polity and identity cease to become important in a shifting political landscape, then eventually the system splinters and balkanizes, which is more or less what happened to the Western Empire.

 

[Mount Suribachi]

At the end it was a simple cost-benefit analysis.

I think it was the same with Northern Great Britain

Basically. Scotland is remote, sparsely populated (even today large swathes of it have the lowest population density in Europe), with little of strategic value. They gave it a bash, the locals fought back, and it wasn't worth the effort to subdue them.

If there was gold in Scotland, you could bet your bottom denarius they'd have roflstomped the place.

 

[Flying Pig]

Too remote with no real resources or political structures worth investing money/manpower into. The Germanii political structues could be managed and mitigated from behind the Rhine without needing to devote valuable resources and manpower to removing by force and Pictish incursions weren't frequent or concentrated enough to warrant more than a wall. Both regions were undeveloped and relatively sparsely populated. Remember the Romans did occupy Dacia but were eventually forced to abandon it.

I'm not sure the Romans really thought like that, though I think your assessment is entirely correct. Modern countries have grand strategies and think in such cost-benefit terms; I think Roman emperors and consuls (who after all had the only word in whether a place was going to be invaded) thought far more in terms of the pursuit of glory, which was a necessary part of the job. Roman emperors were flattered with the title 'expander of the Roman empire' (propagator imperii Romani) long after they stopped doing any meaningful expanding, and during the Republican period the impulse to do something impressive and win a triumph for it was huge - so huge that Augustus had to stop his generals from doing it by slowly banning them from celebrating triumphs. I would be more inclined to look at it like that - Scotland and Germany-beyond-the-Rhine were sparsely populated and lived in by people without great cities, so it was almost impossible to go there and bring back crowds of slaves and wagons full of gold, like Pompey brought back from Asia in the triumph par excellence. If we think about it from the general or emperor's point of view, the effort of going there and trying to conquer the place wasn't worth the return of plunder and glory. The calculation is similar, I suppose, but puts it more firmly in the mind of the person actually making the decision.

 

[innonimatu]

I agree, the roman empire was not planned, it was a series of accidents resulting from the greed and ability of its generals.
But I'll go further and say that I even doubt that the people ultimately making the decisions in modern countries care much about cost-benefit in grand strategy terms.

 

[Flying Pig]

That may be true, but at least they have people paid to do so, the machinery to actually make meaningful calculations, and a culture that requires them to try. How would anyone in Rome, remember, have come to a remotely accurate assessment of the population of Britain before the invasion, or its land area, or the amount of gold in Wales and tin in Cornwall, or any number of important facts?

 

[innonimatu]

That may be true, but at least they have people paid to do so, the machinery to actually make meaningful calculations, and a culture that requires them to try. How would anyone in Rome, remember, have come to a remotely accurate assessment of the population of Britain before the invasion, or its land area, or the amount of gold in Wales and tin in Cornwall, or any number of important facts?

You're right in that there was nearly no information to make a cost-benefit analysis. But that neat-total absence of information, now that you mention it, may have simplified things a lot. If tin came from Cornwall, for example, it would be enough for it to become a good target? And traders knew where their supply came from, even if not where the actual source was located.

I thought about a late medieval parallel: the conquest of Ceuta by Portugal in 600 years ago. It was targeted quite possibly because it was the endpoint of the sahara gold trade route (and also a troublesome pirate heaven). Obviously those routes were diverted by the moroccan rulers when the city was captured. But the portuguese crown kept chasing that gold to its source, taking more cities in the moroccan coast, sailing down the african coast and establishing outposts, until the guinea gold coast was reached.
The actions depended on individual initiatives of several monarchs and captains. On the financing of bankers. Even though the information was incomplete and often the conquered territory turned out to be ruinous to hold and ended up abandoned, there was an economic (and therefore political) purpose to the actions guiding the expansion of a polity. And it was guided by very incomplete information, but because there wasn't much to work with, the next steps (targets) became kind of obvious. Not e cost-benefit analysis, but just plain old greed/search for a profitable war on the basis of the scraps of information available.

 

[ParkCungHee]

That may be true, but at least they have people paid to do so, the machinery to actually make meaningful calculations, and a culture that requires them to try. How would anyone in Rome, remember, have come to a remotely accurate assessment of the population of Britain before the invasion, or its land area, or the amount of gold in Wales and tin in Cornwall, or any number of important facts?

The absesnce of quantifiable asssements is not the same thing as the absence of a meaningful assessment.

A remotely accurate assessment of Britains rough population and size, and standard of living were all reasonably plausible. Even if the Romans didn't have the ability to look at it themselves, they'd have access to people who could and did.

Similarly the amount of gold in Wales or tin in Cornwall. They may have no way of knowing what Tin reserves Cornwall had, but they could certainly discover if Cornwall was producing Tin through ordinary human relations.

These might not have been able to be put into exact calculations, but it wouldn't be hard for a Roman general to tell a wealthy nation from a poor one.

 

[Agent327]

Indeed Roman traders often went where no legion ever treaded. But economic calculations apart, one might just ask: Why go where there was no rich booty to be had to be displayed in triumph? The fairer question then would be: Why would Romans conquer all of Germania and Britannia? Not the other way around.

 

[FriendlyFire]

The fairer question then would be: Why would Romans conquer all of Germania and Britannia? Not the other way around.

Internal Roman empire problems.

And like the Persians before where each generation would expand its empire, until internal weakness, which lead to military defeat and then cause the empire to unravel.

Rome went though its costly internal civil war, several very bad emperors, internal problems, military defeats and then empire unravelled.

 

[Agent327]

As Dachs so eloquently showed, the Western empire was never military defeated. Historians have abandoned looking for a single cause for the 'fall' of the Western empire some time ago. It was a complex and gradual process, not something that happened overnight. Bad emperors, civil war and military defeat plagued the Eastern empire as well. Yet it didn't fall.