Watchtower Möhlin-Lower Weirs

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Watchtower Möhlin-Lower Weirs
Alternative name Unknown
limes Danube-Iller-Rhine-Limes
section Route 2
Dating (occupancy) Valentinian
4th to 5th century AD
Type Turres / Burgus
unit Unknown
size 9 × 9 meters
Construction stone
State of preservation Square structure, foundations of the south wall restored and preserved, west, east and north walls slipped into the Rhine.
place Möhlin
Geographical location 634 076  /  270750 coordinates: 47 ° 35 '11.6 "  N , 7 ° 53' 29.8"  O ; CH1903:  six hundred thirty-four thousand and seventy-six  /  270750
height 282  m above sea level M.
Previous Wallbach-Stelli watchtower (southeast)
Subsequently Watchtower Möhlin-Fahrgraben (west)
Tower location after the renovation in 2014
Roman Watchtower Lower Weirs - Möhlin, AG, Switzerland Image , 2014

Link to the picture
(please note copyrights )

Solidus Valentinians I.
Findings sketch 1918–2014
Images of watchtowers on Trajan's Column
Bronze ace of Constantius

The watchtower Möhlin-Untere Wehren was part of the Roman Danube-Iller-Rhein-Limes and is located in the municipality of Möhlin in the canton of Aargau in Switzerland .

The late antique watchtowers on the Upper Rhine are among the most important Roman legacies on the territory of today's Switzerland. They were built in the 3rd and 4th centuries and were part of a surveillance and alarm chain that was supposed to secure the southern bank of the Rhine against invaders from free Germania. In the canton of Aargau around 30 watchtowers and other military installations from Roman times have been identified that were part of the fortress line of the Rhine Limes. Only the southern longitudinal wall of the watchtower has survived, the rest of the building was washed away and destroyed by the Rhine over the centuries. The ruin was described as early as the 19th century and apparently almost completely demolished for the extraction of building material. It was studied more thoroughly at the beginning of the 20th century. It was then forgotten again until it was exposed and preserved again at the beginning of the 21st century. The most recent excavations have shown that remnants of the wall rubble and layers of waste from the time the watchtower was used have been preserved.

location

His remains are in a bend in the river, directly on a steeply sloping embankment on the southern bank of the Rhine. In the 19th century, Samuel Burkart wrote an even more precise description, who located the watchtower: "... opposite the Hösligraben, a little below the influence of the Wehra [in the Rhine] ...". From this location you could see the opposite bank and the mouth of the Wehra. In addition to the one at the lower weir, two other specimens were discovered near Möhlin, to which there was also a line of sight. These were the Möhlin-Fahrgraben watchtower approx. 1.5 km away and the Wallbach-Stelli watchtower 2 km away. All are easily accessible via the riverside path. The section of the Rhine border near Möhlin belonged to the province of Maxima Sequanorum in late antiquity .

Research history

The “waiting room opposite the castle near Oberschwörstadt” has been known to a wider public since 1871 through descriptions by Ferdinand Keller (1800–1881) and Pastor Samuel Burkart (1881–1969). According to Keller, the "... lying hard on the bank of the Rhine ..." was around 14 feet long and around 2½ feet high at the base in 1871. Burkart held u. a. found that the ruin was much better preserved in the last third of the 19th century: "A few decades ago the tower was said to have been quite high, then parts of it were blasted off and the material obtained was used to improve the narrow streets that passed by." He also wrote that: "... the western [= southern] wall ..." was 9 meters long and 1.6 meters wide. "The eastern [= western] wall has sunk and lies as a compact piece on the dump on the banks of the Rhine." In connection with the construction method, Burkart also refers to similarities to the tower at Möhlin-Fahrgraben. As a result, however, there were no "drafts" in the foundation. H. Voids left by the previous wood reinforcement, visible. The tower site was systematically examined and documented from 1918 to 1919, on behalf of Karl Stehlin (1859–1934) and Jakob Villiger, Swiss Society for the Preservation of Historical Art Monuments. There is no evidence of a medieval use of the watchtower, as in Koblenz. The ruin was quickly forgotten again and was difficult to locate in 2014 due to incorrect coordinates and heavy vegetation.

As part of the project "Research, renovation and mise en valeur of the late antique watchtowers in the canton of Aargau", Roman wall remains near Möhlin (AG) were cleaned, documented and analyzed in 2014. The field work in Möhlin-Untere Wehren was carried out between June and July 2014 by students and employees of the University of Basel. The main task was - in addition to the documentation of the ancient building fabric and the previous restoration measures (measuring, drawing, photographing, describing, creating 3D scans and photogrammetrically corrected wall views) - removing the vegetation, cleaning and preserving the masonry, as well as exposing the Rising or the uppermost part of the foundation. Furthermore, field inspections were carried out in the vicinity of the tower site. After the appraisal, it became apparent that the “facts” of the building fabric as stated by Karl Stehlin had not changed significantly. There was even more building fabric than expected. Not only the actual wall core was preserved, but also parts of the inner and outer wall shell and also some layers of the rising masonry. When digging the roughly 0.2 meter thick humus edge on the land side of the south wall, the remains of wall rubble and ancient layers of waste were also found. However, for conservation reasons, these have not yet been fully investigated. For this reason, exploratory cuts were not made. During the renovation work on the Möhlin-Fahrgraben tower, in comparison with two other late antique towers in the canton of Aargau, it was important to realize that the towers built under Valentinian I have a lot in common, but a very individual one in terms of their construction Have character, such as B. in relation to the size or the presence of wood reinforcements in the foundation area.

Find spectrum

The excavation and restoration of 2014 brought about a significant expansion of the previously known, only very poor range of finds. Of the few Roman finds from the old excavations, a mortar from the 3rd or 4th century and the shard from a southern Spanish olive oil amphora (Dressel 23 type), which was used from the 3rd to the early 5th century, are worth mentioning. The new finds (ceramics) were mostly very small and strongly rounded. It was about ceramics from the 1st to the 4th century (late Rheinzabernware and Argon sigillata). Underneath were the remains of a "Germanic saucepan" with a lip made of gray-black clay, without mica particles, smoothed, with remains of soot and porridge on the outside. The bottom of a glass beaker from the 4th century and a bronze coin are also worth mentioning among the small finds. It is a barely worn ace from the time of Constantius II (337–361), which was struck between 347 and 348 AD in Lugdunum . Among the animal bones that can be dated to the 4th century, only domestic animals, but no game (horses, sheep, goats, pigs and cattle) were found. Only a few wild animal bones were found at the other late Roman sites in the region ( Castrum Rauracense and granary Rheinfelden-Augarten West). In the late antique north-western Switzerland - unlike the provinces bordering to the east - hunting does not seem to have played a major role in obtaining food. The lack of game animals could also reflect the low rank of soldiers stationed here. Three long bone fragments have been assigned to the genus equidae , perhaps the remains of mounts. It could also be food waste. The Teutons ate horse meat, and the proportion of Germanic mercenaries was relatively high among the late antique border guards ( Limitanei ).

development

The tower was built around the year 370 as part of the border reinforcement against the Alamanni north of the Rhine. With the withdrawal of the army from the Upper Germanic-Raetian Limes , the Romans moved the northern border of the empire back to the banks of the rivers Rhine ( Rhenus ), Danube ( Danuvius ) and Iller ( Hilaria ) around AD 260 . After the construction of the first fortifications in the late 3rd and first half of the 4th century, Emperor Valentinian I , probably from 369 to 374, left between Basel ( Basileum ) and Lake Constance ( Lacus Brigantiae ) to strengthen the Limes ( ripa ) build another 50 watchtowers ( turres ) and forts ( castra ). They were in visual contact with each other and were used to monitor traffic on the Rhine and, in the event of an alarm, to relay signals to the troops stationed in the Rhine forts ( Riparenses ). These were in this section under the command of the Dux provinciae Sequanicae . In the winter of 401/402 AD, most of the units had to be withdrawn from the Rhine border in order to be able to defend Italy , the heartland of western Rome , against the Visigoths under Alaric . The Rhine towers were not reoccupied afterwards and left to decay. In 2013, the local community of Möhlin celebrated its 100th anniversary and on this occasion granted a loan for the renovation of the facilities in their community area. The site of the watchtower is now owned by the power plant operator Ryburg-Schwörstadt AG. In the canton of Aargau, 30 Roman watchtowers and other military installations of the late Roman Danube-Iller-Rhine Limes have been located.

Watchtower

It was a stone-built tower or burgus with a square base area of ​​around 9 × 9 meters. The walls on the river side were washed down by the Rhine over time and almost completely destroyed. The fragment of the western wall mentioned by Burkart as well as parts of the inner (Rhine-side) wall shell of the southern wall foundation have disappeared due to slope erosion and frost blasting. Stehlin's findings plan from 1919 shows that a larger fragment of the western wall that had slipped into the river was still preserved or visible. It is conceivable that it is still in situ, i.e. H. is located in the Rhine, which has now been dammed higher by the Rheinfelden power plant . An inspection in 2015 showed that fluvial erosion is also accelerated by beaver burrows . The first cracks in the cast masonry of the conserved south wall give rise to concerns that their preservation in the long term is only possible through structural stabilization of the embankment.

The southern part of the foundation is 9 meters long. Its very hard cast masonry ( opus caementitium ) is interspersed with scattered brick splinters, bone fragments and straw. Only rudiments of the western and eastern corners are left. What have been preserved, however, are fragments of the inner wall shell of the 1.6 meter wide and at least 0.7-0.8 meter high foundation as well as - at least partially - the first and second stone layer of the landside cladding of the rising masonry. The latter consists of unusually large quarry stones made of shell limestone and was originally plastered. The destruction of the wall shell on the Rhine side was favored by the cavity that arose over time when the outermost inlay wood laid parallel to the foundation rotted. The wood reinforcement has completely disappeared today, its construction method could no longer be traced back to the 0.5 meter long, still preserved part of the western wall. It was evidently a question of narrow, very tightly spaced round timbers that were laid in the line of the wall. By installing them, stones and mortar could be saved, and the latter also dried out faster. Stehlin explicitly pointed out that Burkart's alleged lack of wood reinforcement was incorrect. According to Stehlin, the “... completely senseless arrangement of the bar grating ...” can be explained by the fact that the building ground, which consists of a layer of alluvial sand at least 0.8 meters wide, was not stabilized by the workers with previously driven piles (pilots).

There are no clear indications of a surrounding wall and ditch system or palisade. A hollow about 10 meters from the south wall was filled with charcoal-containing sediments. Perhaps there was once a pile of wood or a pile of straw with which the crews of the nearest towers and forts could be alerted with smoke and fire signals. One of the reliefs on the Trajan Column (113 AD) shows watchtowers on the lower Danube, next to it hay or straw stacks for the supply of the horses and a pile of wood for fire signals. A torch is attached to each tower, which was probably also used to transmit messages. The late antique specimens on the Rhine could have looked something similar.

Note

The tower is freely accessible to visitors at all times and has an information board. Climbing the ruin, starting a fire, deliberately damaging the masonry and tampering with the ground are prohibited. No liability is accepted in the event of an accident.

See also

literature

  • Walter Drack : The late Roman border weir on the Upper Rhine. Archaeological Guide of Switzerland, No. 13, second revised edition with reference to older literature, Basel 1993, pp. 18–19.
  • Peter-A. Schwarz: New research on the Late Antique Upper Rhine Limes in the canton of Aargau I. The watchtowers Koblenz-Kleiner Laufen, Möhlin-Fahrgraben and Möhlin-Untere weirs. With contributions by Sandra Ammann, Sabine Deschler-Erb, Juha Fankhauser, Lukas Freitag, Simon Jeanloz, Tina Lander and Daniel Schuhmann. PDF, pp. 59-66
  • Samuel Burkart: The Roman fortifications on the Rhine from Mumpf to Kaiseraugst. In: Anzeiger für Schweizerische Altertumskunde No. 5, 1903/04, pp. 256–267.
  • Karl Stehlin, Victorine von Gonzenbach: The late Roman watchtowers on the Rhine from Basel to Lake Constance. 1. Lower route: from Basel to Zurzach. Institute for Prehistory and Protohistory in Switzerland, Basel 1957.

Remarks

  1. cf. Watchtower Koblenz-Kleiner Laufen , watchtower Möhlin-Fahrgraben

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