LIMES, RHINE
Switzerland.
Between Basel
and Lake Constance. After the abandonment of the defensive system E of the Rhine and Danube, known as the
Upper German-Raetian Limes between A.D. 254 and 260,
the Rhine as far as Lake Constance again became a
boundary of the Roman empire. A new frontier system
was built after the end of the 3d c. A.D. In its Swiss section more of the forts and the smaller structures between them have been preserved than exist below Basel.
Literary (esp.
Amm. Marc. 27-30 passim) and epigraphical sources indicate that this system was built in
two periods: under Diocletian and Constantine (
CIL
XIII, 5249, 5256: Castella Vitudurum, Tasgaetium, A.D.
294), and under Valentinian I (
CIL XIII, 11537-38 =
Howald-Meyer nos. 339-40, pl. 40: Burgi Summa Rapida,
Rote Waag, A.D. 371). It is probable that the Rhine limes
was completed in 368-71, before the Raetian and Pannonian limes on the Danube.
The system proved effective until the main body of
Roman troops was withdrawn to Italy in A.D. 401. Some
of the units garrisoned along this part of the limes have
been identified: Legio I Martia (stamped tiles in Gastrum Rauracense); Legio VIII [August] anensium (building inscriptions in Summa Rapida and Rote Waag);
Cohors Herculea Pannoniorum (Arbor Felix,
Not. Dign.
0cc. 35.34); Numerus barcariorum Confluentibus sive
Brecantia (both harbors on Lake Constance,
Not. Dign.
0cc. 35.32).
Fundamentally the Rhine limes was intended to hold
the frontier by multiplying the fortifications on the left
bank and by safeguarding the waterways as a supply
line for the frontier troops. To achieve this various structures were erected: 1) larger forts at the main crossings
of the Rhine (often strengthened by a fortified bridgehead on the right bank), as well as on trunk roads; 2)
fortified landing places for boats supplying the army;
3) signal towers and watchtowers assuring communication between the larger forts; 4) fortified supply depots
near the main waterway. These 4th c. structures varied
greatly in plan and size, and cannot be more precisely
dated; moreover, some of them were earlier installations
renovated on the same site. Archaeological evidence,
however, indicates that building activity in the earlier
phase concentrated on the larger forts on the Rhine and
the trunk roads; in the Valentinian phase on the bridgeheads on the right bank of the Rhine, the landing places,
watchtowers, and supply depots.
The larger forts on the Rhine from Basel upstream
were Basilia, Castrum Rauracense, Tenedo, Tasgaetium;
on the military road from Basel to Raetia, Castrum Vindonissense, Vitudurum, Ad Fines, Arbor Felix; on Rhine
tributaries and adjacent roads, Salodurum, Ollodunum,
Altenburg (on the Aare), Turicum (on the Limmat).
Fortified landing places have been identified at Tenedo,
Tasgaetium (?), Arbor Felix, and Salodurum. Known
supply depots are two identical structures in Mumpf and
Sisseln which have semicircular annexes on the narrow
sides of buildings 25 x 15 m, possibly towers. Over 40
watchtowers on the Rhine have been identified, most of
them excavated, and some preserved. They were usually
at the edge of the river and often as little as 1.2-1.5 km
apart. Built of stone, they varied in size, but the majority were square and 8-10 m on a side (max.: 18 x 18;
18 x 26 m). The walls, on the average, were 1.5 m thick
(2.5-3.5 m in the larger ones). A peculiarity is the
strengthening timber pilework in both foundations and
walls. The towers had several stories, supported by
wooden post(s); they also had windows and wooden
galleries. The entrance was from the river. Each was
surrounded by a rampart (sometimes enclosing wooden
outbuildings), a wide berm, and a ditch. Small landing
facilities for boats can be assumed.
BIBLIOGRAPHY
F. Staehelin,
Die Schweiz in römischer
Zeit (3d ed. 1948) 267-315
MPI; K. Stehlin & V. von
Gonzenbach,
Die spätröimischen Wachttürme am Rhein
von Basel bis zum Bodensee 1 (1957)
MPI; I. Garbsch,
“Die Burgi von Meckatz und Untersaal und die valentinianische Grenzbefestigung zwischen Basel und Passau,”
Bayerische Vorgeschichtsblätter 32 (1967) esp. 51-82
M; H. Schönberger, “The Roman Frontier in Germany,
an Archaeological Survey,”
JRS 49 (1969) esp. 177-97
M;
E. Vogt, “Germanisches aus spaetroemischen Rheinwarten,”
Provincialia, Festschritt R. Laur-Belart (1968)
632-42.
V. VON GONZENBACH
