(Caerleon) Monmouthshire, S Wales.
The base fortress of Legio II Augusta, which had participated in the invasion of Britain, A.D. 43; founded by
Julius Frontinus during the conquest of Wales (Tac.
. 17) in 74-75. Now a village on the river Usk,
4.8 km upstream of Newport (Mon.), Caerleon has been
extensively excavated since 1926. Most of the plan can
be reconstructed, but only the amphitheater and a centurial barrack in the W corner, together with parts of the
adjacent defenses, are visible today.
The fortress occupies a position very similar to that
of Legio XX V. V. at Chester—at the roots of the Welsh
peninsula, on a navigable estuary for ease of supply, but
above danger of flooding. Between them, the two fortresses maintained the military occupation of Wales,
and some of the auxiliary forts at important valley
junctions provide evidence of a legionary connection
(brick stamps, inscriptions). The tactical position of
Caerleon is particularly good since it lies in a wide
bend of the Usk and is additionally protected by a small
tributary on the E. To the NW rises a hill crowned by
a hate Iron Age hill-fort. Running water was carried by
20 cm head pipes from an unknown source.
The fortress is a rectangular enclosure with rounded
corners, oriented NW-SE and 90 by 18 m. an area
of 20.6 ha. The defenses first consisted of a clay bank
formed of upcast from a single ditch 9 m wide; the
rampart was strengthened with timbering, but nothing is
known of the gateways and turrets of the initial period.
In the 2d c. the bank was cut back, and a wall (still in
parts visible) built, with a double gateway in each side;
there were internal turrets at intervals of ca. 45 m.
Extensive rebuilding at the S corner of the wall may be
related to damage sustained during a revolt of the
Silures while the legion was supporting Albinus in
Gaul, in 196-197.
The interior is divided into three lateral zones by the
via principalis (between the NE and SW gates) and the
via quintana. In the center of the middle, or administrative zone stood the headquarters (principia): it is mostly
under the present church, but part of the basilica (64.8 x
26.85 m internally) was excavated in 1968-69. The roof
was supported by lofty colonnades of Bath stone, in
front of the N row of which there had been inscribed
plinths for statues, two of bronze (only scraps remain):
cf. the statues erected in a similar position at Lambaesis.
The building was dismantled at the end of the 3d c.
On its right side, three of the five houses for primi
ordines centurions, together with parts of the corresponding 10 barracks for the milhiary first cohort, have been
excavated. On the left side, parts of six barracks for a
quingenary cohort are known, together with stabling for
the 120 equites, or scouts, of the legion. Behind the
principia lay the palace of the legate (praetorium), with
an internal oval court as at Xanten, but approached
through a large basilica for public audience. On the
right side of the praetorium is a great basilica exercitatoria, for drill in wet weather; adjacent are some rows of
magazines. The nature of buildings in an insula farther
SW are as yet unknown. On the left side of the pinetorium
is a large courtyard building identified as workshops, consisting of large halls or stores; residential accommodation projects into the courtyard. The contents
of an insula farther NE are unknown.
The retentura is entirely given over to centurial barracks arranged longitudinally and accommodating two
quingenary cohorts; 12 barracks, on either side of the
decumanus, led to the NW gate. The barracks measured
ca. 72 by 12 m, about a third allocated to the centurion
and the rest divided into 12 double cubicles for the men.
The praetentura is bisected by the via praetoria leading from the SE gate to the headquarters. Inside the SE
defenses another long range of 24 barracks completes
the accommodation for the 10 cohorts of the legion.
The remaining ground on the SW side of the praetentura
has not been much explored; it is likely that granaries
occupy part of it. On the NE side, recent excavation
has revealed parts of the hospital and the large internal
baths, both of which were demolished about the end of
the 3d c. The hospital consists of rows of small wards
arranged around three sides of a square court, with a
second concentric range within; a large operating theater
projected into the court from the fourth and SE side.
The baths comprised a large basilica (63.3 x 23.4 m)
opening from the via principalis, a frigidarium with
several piscinae, and heated accommodation, the most
important elements of which (calidarium, etc.) are inaccessible. On the SW lay a palaestra with porticos on
three sides, containing a pool (40.5 x 5.4 x ca. 1.2 m)
reminiscent of the palaestra of Herculaneum.
The entire block of internal buildings is divided from
the defenses by a wide street. Various turrets had cookhouses built in front of their ground-floor entrances and
numerous rampart magazines are known. Latrines have
been excavated in the S and W corners and probably
existed on the E and N. Some of the principal buildings
were erected in stone from the beginning, but the barracks and the hospital were first built of timber on
cobble footings. The stone replacements are of 2d c.
date, and there was widespread rebuilding and repair in
the early 3d c.
The environs of the fortress include elements of a
small vicus cannabarum on the SW, which seems never to
have reached urban proportions, perhaps because the
cantonal capital of the Silures (Venta Silurum) was not
far distant. Shops, a mansio (?), and other buildings are
known, while temples of Mithras, Jupiter Dolichenus,
and Diana are epigraphically attested. The area is divided by a continuation of the main street down to the
Usk, where 3d c. wharves have been excavated; the civil
settlement is separated from the fortress, NW of this
road, by a walled parade ground (ca. 150 x 207 m), and
on the SE side by the amphitheater (80.1 x 66.6 m; the
arena, 55.2 x 40.95 m). The structure is partly set into
the ground, the upcast being revetted by stout walling
as a basis for the wooden seating. There are four principal entrances, two on the short axis with boxes above,
and four subsidiary ones; all, except the two that led
directly into the arena, had dens at the level of the
arena. A large bath house is adjacent, and another is
known on the SE side of the fortress. On the S side of
the Usk and along roads leading W and NE there were
cemeteries, including at least two mausolea belonging
to burial clubs; cremation was the predominant rite.
The finds are housed in the Legionary Museum of
Caerleon (branch of the National Museum of Wales)
and at the National Museum in Cardiff.
J. E. Lee, Isca Silurum
; G. C.
Boon & C. Williams, Plan of Caerleon
; Boon, Isca: the Roman Legionary Fortress at
See also excavation reports: JRS
16ff (1926ff) summariesPI
78 (1928) amphitheaterMPI
; Monmouthshire Antiquary
G. C. BOON