Map of Upper Germanic & Rhaetian
The Limes Germanicus
for Germanic frontier
) was a remarkable
line of frontier (limes
) forts that
bounded the ancient Roman provinces of Germania Inferior
, Germania Superior
, and divided the Roman
and the unsubdued Germanic
, from the years 83 to 260. At its height, the
limes stretched from the North Sea outlet of the Rhine to near
Regensburg on the Danube.
The Limes Germanicus was divided into:
The total length was 568 km (341 miles). It included at least 60
castles and 900 watchtowers.
Reconstructed Limes near Saalburg,
Reconstructed stone wall in
In the foreground: stone tower "WP 12/77"
Roman border defences have become much better known through
systematic excavations financed by Germany and through other
research connected to them. In 2005, the remnants of the Upper
Germanic & Rhaetian Limes were inscribed on the
of UNESCO World Heritage Sites as Frontiers of the Roman Empire.
Saalburg is a reconstructed fortification and museum of the
Limes near Frankfurt.
emperor who began to build fortifications along the border was
Augustus, shortly after the
devastating Roman defeat in the Battle of the
Teutoburg Forest in 9 AD.
Originally there were numerous
Limes walls, which were then connected to form the Upper
along the Rhine and the Rhaetian
along the Danube. Later these two walls were linked
to form a common borderline.
14 to c. 73
death of Augustus (14 AD) until after 70
AD, Rome accepted as
her Germanic frontier the water-boundary of the Rhine and upper
Danube. Beyond these rivers
she held only the fertile plain of Frankfurt, opposite the Roman border fortress of Moguntiacum
(Mainz), the southernmost slopes of the Black Forest and a few scattered bridge-heads.
northern section of this frontier, where the Rhine is deep and
broad, remained the Roman boundary until the empire fell. The
southern part was different. The upper Rhine and upper Danube are
easily crossed. The frontier which they form is
inconveniently long, enclosing an acute-angled wedge of foreign
territory between the modern Baden and
W√ľrttemberg. The Germanic populations of these lands seem
in Roman times to have been scanty, and Roman subjects from the
modern Alsace-Lorraine had drifted across the river eastwards.
motives alike of geographical convenience and of the advantages to
be gained by recognising these movements of Roman subjects combined
to urge a forward policy at Rome, and when the vigorous Vespasian
had succeeded Nero
a series of advances began which gradually closed up the acute
angle, or at least rendered it obtuse.
Remains of the Limes.
advance came about 74 AD, when what is now Baden was invaded and in
part annexed and a road carried from the Roman base on the upper
Rhine, Stra√üburg, to the Danube just above Ulm.
point of the angle was broken off.
The second advance was made by Domitian
about 83 AD. He pushed out from Moguntiacum, extended the Roman
territory east of it and enclosed the whole within a systematically
delimited and defended frontier with numerous blockhouses along it
and larger forts in the rear. Among the blockhouses was one which by
various enlargements and refoundations grew into the well-known
Saalburg fort on the Taunus near
This advance necessitated a third movement,
the construction of a frontier connecting the annexations of AD 74
and AD 83 . We know the line of this frontier which ran
from the Main across the upland Odenwald to the upper waters of the Neckar and was
defended by a chain of forts.
We do not, however, know its
date, save that, if not Domitian's work, it was carried out soon
after his death, and the whole frontier thus constituted was
reorganised, probably by Hadrian
, with a
continuous wooden palisade
Rhine to Danube.
Hadrian and the Antonines
The angle between the rivers was now almost full. But there
remained further advance and further fortification. Either Hadrian
or, more probably, his successor Antoninus Pius
pushed out from the Odenwald
and the Danube, and marked out a new frontier roughly parallel to,
but in advance of these two lines, though sometimes, as on the
Taunus, coinciding with the older line. This is the frontier which
is now visible and visited by the curious. It consists, as we see
it today, of two distinct frontier works, one, known as the
Pfahlgraben, is an earthen mound with stakes on top and ditch in
front of the mound, best seen in the neighbourhood of the Saalburg
but once extending from the Rhine southwards into southern Germany.
other, which begins where the earthwork stops, is a wall, though
not a very formidable wall, of stone, the Teufelsmauer; it runs
roughly east and west parallel to the Danube, which it finally
joins at Heinheim near Regensburg.
The southern part of the Pfahlgraben is
remarkably straight; for over 50 km it points almost absolutely
true for Polaris
Tower of the Limes
This frontier remained for about 100 years, and no doubt in that
long period much was done to it to which precise dates are
difficult to fix. It cannot even be absolutely certain when the
frontier laid out by Pius was equipped with the manpitts and other
special fortifications. But we know that the pressure of the
barbarians began to be felt seriously in the later part of the 2nd
century, and after long struggles the whole or almost the whole
district east of the Rhine and north of the Danube was lost,
seemingly all within one short period, about 250.
Late Roman empire
invasions in the late 3rd century led to the abandonment of the
so-called "Upper Raetian Limes" in favour of a Roman defence line
along the rivers Rhine, Iller and Danube (Donau-Iller-Rhine-Limes) with watch towers in
sight contact and heavily fortified castra at important passes
(e.g. Castrum Rauracense instead of the previously
Raurica near to Basel) and in the
hinterland of the frontier (e.g. Vindonissa in today's Switzerland).
Description and functionality of the limes
The limes itself is a relatively simple construction. It is similar
to the fortification that a travelling troop of Roman soldiers
would construct every evening to protect the camp from attacks. On
the outside, the soldiers dug a ditch. The earth from the ditch was
used to build a mound. On top of the mound stakes were attached.
The Limes had a deeper ditch and a higher mound. The stakes were
higher too and on several parts of the limes, instead of stakes
there was a simple wall.Behind the wall/mound a system of control
towers, built of wood or stone, was installed, each within sight of
the next one, and usually able also to signal to the forts several
kilometers to the rear.
The limes was never able to prevent whole Germanic tribes from
entering the territory of the Roman empire. This was not the
intention of the builders. Near the watch towers, the limes was
open to passage, especially by traders or persons coming to live or
work within the empire. The purpose of the limes was control of the
traffic. To cross the limes it was necessary to pass the towers,
and so come to the notice of the garrison, or to climb or destroy
the wall or the stakes. Only individuals or small groups could
climb the obstacles without being noticed, and they could not drive
stolen livestock with them. Large groups would be noticed. They
could destroy one or several towers, but this also would come to
the attention of the Romans. This knowledge of all groups crossing
the border was important for the Roman empire. For a territory as
large as the Roman empire, there were amazingly few soldiers.
Almost all of the legions were based close to the frontiers. Any
hostile group who managed to pass this area of defense could travel
within the empire without significant resistance. The purpose of
the limes was early warning of attack, deterrence of casual
small-scale raiding, and the ability to react while the enemy was
near the legions.
Towns and cities along the limes
Upper Germanic Limes
Lower Germanic Limes
- A good English account can be found in H. F. Pelham's essay in
Trans. of the Royal Hist. Soc. vol. 20, reprinted
in his Collected Papers, pp. 178-211 (Oxford, 1910), where
the German authorities are fully cited.
- D.I. Woolliscroft, Roman Military Signalling. Stroud and
Charleston: Tempus Publishing, 2001. Pp. 191. ISBN 0-7524-1938-2. A
study mainly of intervisibility along the Rhine and British