At the confluence of Rhine and Moselle. The name is
first mentioned by Suetonius (Calig
. 8; later literature:
. 371; Tab. Peut
.; Geogr. Rav
. 4.26, p. 234 = 4.24,
p. 227 P.; CIL XIII, 9158, i, Z.4). The earliest Roman
finds from the area of Koblenz date from Tiberian times.
Necropoleis are located at Löhrstrasse, Kaiserin Augusta-Ring (today Moseiring), Neuendorf on the left bank
of the Moselle. During construction work on the Münz-platz in 1952 the W surrounding trench of an auxiliary
castellum from the first half of the 1st c. A.D. was found.
The castellum extended from the corner of Marktstrasse
and Münzplatz ca. 150 m E, ran N to the Moselle and
S to the Late Roman wall. Finds from the bottom of the
trench show that this camp already existed in late Tiberian or early Claudian times. The main function of
the auxiliary castellum must have been to guard the
Moselle crossing. The existence of a bridge across the
Nahe has been established for the year A.D. 70. It is therefore likely that the Roman Rhine road crossed the Rhine
tributaries via bridges. During work on the river in
1865 and 1894 thousands of wooden piles with iron tips
were removed from the river bed, remains of a Moselle
bridge of Middle or Late Imperial times. Numerous
spolia from Roman monuments were found in and next
to pile gratings 10.6 m wide, also several thousand coins
on the E side of the first pillar in the river. The Roman
bridge was 15 m wide and 16.3 m high, had 9 pillars
and 10 arches. On the Roman road coming from Mogontiacum (Mainz) through the Rhine valley 6 milestones
were found side by side in Koblenz, with the dates 44-45,
97 and 98-99 (CIL
XIII, 9145-9149). They give the distance “A Mogontiaco” as 59 Roman miles (87.32 km).
The Roman road followed as the Löhrstrasse to the
Müinzplatz, bypassed the castellum, probably on the W
side, crossed the Moselle bridge and led through the Neuwied basin down the Rhine to Andernach (Antunnacum).
The auxiliary vicus extended E of the Löhrstrasse to the
bank of the Rhine and N of the Schlossstrasse to the bank
of the Moselle.
During the rebellion of the Batavi, the auxiliary castellum was destroyed (name of the garrison still unknown).
After the spring of A.D. 70 no regular Roman military
units were stationed in any castellum N of the Nahe. Possibly the Castellum Koblenz was rebuilt after the Batavi
rebellion (stone castellum?) and continued as a road
castellum in the rear of the limes. The civilian settlement
continued to exist in the 2d and 3d c. There was possibly
a customs station in Koblenz (CIL
XIII, 7623). After the
first invasion by the Franks in 258, the limes area on
the right side of the Rhine was lost. As in Augustan times,
the Rhine was once more the NE border of the Roman
imperium. During the Frankonian raids Koblenz was
destroyed, as documented by the layer of rubble from the
3d century A.D. The reconstruction of the town, including
strong fortifications, took place during the rule of the first
tetrarchy when Maximianus restored the safety of the
Gallic provinces. The late Roman castellum—a rectangular structure with 2 arched sides, 19 round towers, 16 to
25 m high interturria and a gate in the S (area 5.8 ha)—extended from the Münzplatz in the W to the Florin
church in the E, and from the Liebfrauenkirche in the S
to the bank of the Moselle in the N. The fortification was
still extant in 354. A section of milites defensores was
stationed in Koblenz in the 4th c. under the command
of a praefectus who was under the dux Mogontiacensis,
commander of the frontier garrisons of Germania Prima
from Selz (Saletio) to Andernach (Antunnacum) (Not.
. 41). This late Roman Koblenz probably fell
without trouble to the Franks after the withdrawal of
the Roman troops in 402.
J. Hagen, Römerstrassen der Rheinprovinz
(1931) 17ff; A. Günther, “Das römische Koblenz,” BonnJbb
142 (1937) 35ff; id., “Die Kunstdenkmäler des Landkreises Koblenz,” Die Kunstdenkmäler der Rheinprovinz
16 (1944) 7ff; id., Die Kunstdenkmäler von Rheinland-Pfalz. 1: Die Kunstdenkmäler der Stadt Koblenz
(1954) 2ff; id., “Verf., Kastell Koblenz,” BonnJbb
160 (1960) 168ff.