name goes back to a Celtic god Mogon or a den Mogontia, but no important Celtic settlement has been found in Mainz. During the reign of Augustus, two legions built a fortified camp here on a rise opposite the mouth
of the Main, between 15 and 12 B.C. From then on it
was one of the important military bases for Roman campaigns against the Germanic tribes. Two legions were
always stationed in Mogontiacum up to the time of
Domitian. The garrison was reduced to one legion after
the Saturninus rebellion of 88-89. It has been proved that
the Legio XXII Primigenia Pia Fidelis was stationed in
Mogontiacum from A.D. 92 until the first half of the 4th c.
Abandoned no later than the middle of the 4th c., the
camp is mentioned several times in literature (Tac. Hist
4 passim). Archaeological exploration of the camp has
been very limited though the outline of the fortifications
is known (area ca. 36 ha). Except for a few minor
ruins, only the military bath buildings are known within
the interior. From Augustan to Flavian times the fortifications and interior buildings were of wood; several
building periods can be established. Later, the fortifications and inner buildings were rebuilt in stone. Today
nothing can be seen of the legionary camp.
A civilian settlement around the camp developed
during the 1st c. A.D. and was subdivided into several
vici. In the reign of Domitian, Mogontiacum became
the main town of the province Germania Superior and
the seat of the governor, a legatus Augusti pr. (pr. with
the rank of consul). The center of the civilian settlement
was between the legionary camp and the Rhine, under
what is today the old town of Mainz. Until the 4th c.,
it did not have municipal status although it developed
early the appearance and functions of a town. The excavated amphitheater (no longer visible) was comparable
to the largest in Gaul. Not until about 355 did Mogontiacum become a municipium. A wall around the civilian
settlement was built in the middle of the 4th c., parts
of it possibly earlier. The wall surrounded an area of ca.
120 ha. Because this area is completely built-up today,
archaeological excavations are not feasible. The Roman
bridge from Mogontiacum across the Rhine is shown
on a Late Classical lead medallion. None of it exists,
but the bridge piers had been investigated before their
destruction in the 19th c.
In the second half of the 4th c. the town was the seat
of the dux Mogontiacensis, who was the military commander of a sector of the Rhine frontier (Not. Dig
41). Roman occupation ended in 406 when the Roman
troops abandoned the Rhine frontier. However, the town
continued, although greatly reduced, as bishopric.
Today the so-called Römersteine, pillars of an aqueduct that provided water for the camp (probably of
Flavian times), can be seen in Mainz-Zahlbach. In the
modern citadel of Mainz is a large Roman tombstone,
the Eichelstein; it is probably not identical with the
cenotaph of Drusus mentioned by Eutropius 7.13. A part
of the old town wall still exists on the Kästrich, in part
modified by mediaeval reconstructions. The Late Roman foundations of the town wall show spolia, among
them stone inscriptions and fragments from various
buildings (the so-called octogon building, the Dativius
Victor Arch, reliefs from a Flavian victory monument).
The most important finds are in the Mittelrheinisches
Landesmuseum in Mainz; among them are numerous military and civilian stone inscriptions and the large Jupiter column. Worth mentioning also is the Römisch-Germanisches Zentralmuseum, an archaeological research center.
D. Baatz, Mogontiacum, Limesforschungen
; H. v. Petrikovits, “Mogontiacum—das römische Mainz,” Mainzer Zeitschrift
58 (1963) 27-36; Mainz, Führer zu vor- und frühgeschichtlichen Denkmälern
11 (1969) [publ. by Römisch-Germanisches Zentralmuseum, Mainz]MPI