GESORIACUM BONONIA
(Boulogne) Nord, France.
In the Belgica province of Gaul. The history of
the city that grew up around the two sites is characterized by the alternation of the names Bononia and
Gesoriacum, as the city's center of gravity shifted from
one place to the other. The name Bononia was probably
used to designate the Celtic oppidum and was still used
by Tiberius, who stayed there in A.D. 4. But the name
Gesoriacum, first mentioned in the text of Florus (2.30;
between 12 and 9 B.C.), had already appeared by this
time, and the city had probably also begun to take on
the function of a harbor, as Caesar had foreseen (Portus
Itius). For over three centuries only Gesoriacum was
important—the lower city that developed around an expanding port. Gesoriacum acquired a famous lighthouse
under Caligula, who came here in A.D. 40 to stage a
simulated embarkation for Britain; and it was from here
in 43 that the fleet actually sailed. From that time on,
Gesoriacum, home of the Classis Britannica, was the
port linking the continent with Roman Britain.
At the end of the 3d c. the name Gesoriacum was
replaced by Bononia; after the catastrophes of the mid
3d c. the city withdrew to the high fortified ground to
the NE and a large part of the Empire city was abandoned. The construction of the city walls and founding
of the upper city may probably be attributed to Carausius, commander of the fleet responsible for protecting
the litus Saxonicum against pirates. In 293 Carausius'
forces, revolting against the authority of the Tetrarchy,
were besieged by Constantius Chlorus; after the transfer
of power, he named the upper city Bononia, thereby
acknowledging himself to be the usurper.
Nevertheless, at the beginning of the 4th c. the military
port was in full operation (bricks stamped Classis Britannica, from the Constantinian period). The end of
Bononia oceanensis, as it is called on coins, dates from
the beginning of the 5th c.; the city is mentioned one
last time as the base of the usurper Constantine III, who
disembarked there with troops being recalled from Britain. The abandonment of that province was fatal for
Boulogne, which is not included in the Notitia Dignitatum and was not to come to life again until Charlemagne's time. All that can be seen on the site are a few
remains of a barbarian settlement and some Merovingian
tombs.
Systematic excavation is recent and has produced no
spectacular results. The site and area of expansion of
the Empire city, Gesoriacum, are roughly marked by its
necropoleis: three cemeteries—to the NW (between the
Vallon des Tintelleries and the hill on which the upper
city stands), E (N of the modern Rue du Viell-Atre)
and S (at the gates to the suburb of Brequerecque)—bound an urban area of 40-50 ha. Thus Gesoriacum
spread out along the shore; in antiquity it was a cove
but it silted up in the Middle Ages and was drained in
the 17th c. This so-called Anse de Brequerecque was
the site of the Roman port, S of the upper city, not NW
in the Vallon des Tintelleries where the mediaeval port
developed. This location is confirmed by the discovery
of traces of buildings belonging to the naval base near
the Rue de la Port Gayole and the Rue Saint-Marc, and
of a large quantity of tiles and bricks stamped with the
fleet's seal in the same sector. The residential areas grew
up around the harbor installations, the wealthiest houses
probably occupying the higher ground to the NE, away
from the marshes.
The upper city, which was to become the essential city
center in the 4th c., was occupied at least from the
Flavian period on; this is attested by the recent discovery
of a series of basins and by a 19th c. reference to some
remains under the church large enough to have belonged
to an important building (still not properly identified).
But the city was still sparsely settled; the center of activity was farther down, near the right bank of the river.
The orientation of certain mediaeval and modern streets
suggests a grid plan, but it is not certain that the grid
covered the whole city, especially around the ancient
port. As to Caligula's lighthouse, it was partially preserved up to the 18th c. (the Tour d'Ordre) and stood
outside the city, to the NW. According to ancient descriptions, it was built of alternating courses of stone
and bands of brick. Finally, the Empire city does not
appear to have had a surrounding wall, judging both
from the lack of archaeological evidence and from the
vulnerability of the city and the various installations of
the classis which were burnt down, probably in the 3d c.
invasions.
In the Late Empire, on the other hand, a system of
ramparts was erected; the upper city was ringed with a
wall which can still be detected at certain points. The
mediaeval rampart (c. 1231), which is still visible, rested
on Roman substructures on the NW and NE, as proved
by excavation; on the SW and SE the mediaeval wall
was apparently some distance behind the line of the
Roman wall, whose plan is incompletely known. Essentially the upper city rampart formed a rectangle ca. 450 x
300 m, enclosing a citadel of ca. 13 ha. The towers and
gates cannot be precisely located. This system of fortification was completed when two parallel ramparts were
built in the Late Empire. Starting from the SW Bononia
wall, the ramparts probably extended from the upper city
down to the shore, ensuring protection of an area of ca.
20 ha. This second system of defenses, built to protect
old sections of the Empire city, indicates that this part
of the lower city (its boundaries are marked by a few
late cemeteries) was still active as a city and harbor in
the 4th c. The archaeological finds are housed in the
Boulogne municipal museum.
BIBLIOGRAPHY
J. Heurgon, “Les problèmes de Boulogne,”
REA 50 (1948) 101; 51 (1949) 324; id., “De
Gesoriacum à Bononia, Hommages Bidez-Cumont,”
Coll.
Latomus II (1949) 127; E. Will, “Les remparts romains
de Boulognes-sur-mer,”
Revue du Nord 42 (1960) 363;
id., “Recherches sur le développement urbain sous l'empire romain dans le nord de la France,”
Gallia 20 (1962)
79; id., “Boulogne et la fin de l'Empire . . . ,”
Mél.
Renard, II (1969) 820.
C. PIETRI
