CASTRA PRAETORIA
* the barracks of the praetorian
guard, built by Tiberius
at the instigation of Sejanus in 21-23 A.D. when these
troops were
quartered permanently within the city (Suet. Tib. 37; Tac.
Ann. iv. 2;
Cass.
Dio lvii. 9. 6; Schol.
Iuv. x. 95). They were in the
extreme north-
eastern part of Rome, just beyond the inhabited district
(Plin.
NH iii. 67 ;
Suet. Nero 48; Not. Reg. VI), about 500 metres east of the
agger, on a
site that was one of the highest in Rome (59-60 metres
above sea-level),
and commanded both the city and the roads leading to the
east and
north-east. The camp was constructed on the usual Roman
model,
forming a rectangle 440 metres long and 380 wide, with
rounded corners.
The longer axis, the cardo maximus, ran nearly north and
south, and
at its ends, in the middle of the shorter sides, were the
porta praetoria
and the porta decumana. It is not certain, however,
whether the porta
praetoria was on the north side or the south (HJ 387-388
north, Antonielli,
BC 1913, 31-47 south). The cardo maximus did not divide
the castra
equally, and the gates at its ends, porta principalis dextra on
the west and
porta principalis sinistra on the east, were 190 metres from
the north side
and 250 from the south.
1
The original walls of Tiberius (
AJA 1912, 398) are of
brick-faced
concrete, 4.73 metres high where they are still preserved
(see below), and
had battlements and turreted gates (Ill. 13) (Tac.
Hist. iii.
84;
Herod. vii.
11.12). On the inside of the wall were rows of vaulted
chambers occupied
by soldiers, some of which, on the north and east sides,
are still visible.
They were 3 metres high, of opus reticulatum lined with
stucco, and
above them ran a paved walk for the guards (for the
discovery of these
and other chambers in the castra, see BC 1872-3, 5, 12-14;
1876, 176-178).
A view of the principia is perhaps to be found on one of
the 'Aurelian'
panels of the Arch of Constantine (
PBS iii. 263). As would
be expected
from the importance of the praetorian guard, the castra
are mentioned
frequently in the literature of the empire (Tac.
Ann. xi. 31;
xii. 69;
xiii. 14;
xv. 53, 59;
Hist. iii. 84; Suet. Claud. 21; Hist.
Aug. Did.
Iul. ii. 6;
Max.et Balb.x. 5; Frag.Vat. 195; Herod.ii.6,7; vii. II, 12;
Chron. 147)
and in inscriptions (
CIL vi. 9277, 9661, 9992), especially
those on lead
pipes, which show the care expended by successive
emperors on the
water supply of the barracks (
CIL xv. 7237-7244;
2 LA
438-442, Nos.
103-127).
Two interesting coin types of Claudius represent on the
reverses his
reception in the praetorian camp after the murder of
Caligula: the
legends are respectively
imper(ator) recept(us), which is
shown in the
type with a soldier on guard, and
praetor(ianus) recept(us)
(i.e. infidem),
i.e. the acceptance by Claudius of the fealty of the
praetorians-an idea
well symbolised by the clasping of hands (BM Imp. p.
cliii; Claud. 5,
8-10, 20-25, 28-37, 38 and p. 174 n.. =Cohen, Claud. 40-
46, 77-80).
The regular name of the barracks was castra praetoria,
but they seem
also to have been called vulgarly castrum praetorium (
CIL
xv. 7239 b, c)
and castrae praetoriae (ib. d); and in the Middle Ages
castra custodiae
(
BC 1914, 399, 402). The cohortes urbanae were also
quartered here
before the construction of the Castra Urbana.
Aurelian incorporated the castra in his line of
fortification, which
joined the castra at the north-west corner and again near
the middle of
the south side. The north and east wall of the castra thus
formed the
continuation of the Aurelian wall, and its original height
was increased
by an addition of 2.5 to 3 metres at the top and by digging
away the soil
about its foundations to a depth of 2.3 metres (Homo,
Aurelien 244-245,
266-268). The original wall can be distinguished from that
of Aurelian
by the difference in brickwork and by the outline of the
battlements
(LR fig. 171 shows Aurelian's battlements, and not those
of Tiberius;
for the latter, see RA 41-46, and especially fig. 46, in
which both the lines
of battlements are seen). The gates on the north and east
sides were also
walled up by Maxentius (?). In 312 Constantine
disbanded the praetorian
guard and dismantled their barracks, presumably by
destroying the
inner walls that had not been used by Aurelian (
Zos. ii. 17;
Aur. Vict.
Caes. xl. 25; Lact. de mort. pers. 26), although a part of
the west wall
is reported as standing in the sixteenth century (
LS ii.
243; HJ 389, n. 41).
Within the castra was the shrine of the standards of the
guard (
CIL
vi. 1609;
Herod. iv. 4. 5;
v. 8. 5-7), a tribunal, on which
these standards
were set up, restored by the statores attached to the
barracks (
CIL vi.
3559;
WS 1902, 356-358), a shrine of Mars (
CIL vi.
2256), and an
armamentarium, or imperial armoury, mentioned twice by
Tacitus (
Hist.
i. 38. 80) and in two inscriptions (
CIL vi. 999, 2725;
RE ii.
1176).
In the north part of the castra, east of the north gate,
was an
altar of Fortuna Restitutrix, of which the remains were
found in 1888
in a room paved with black and white mosaic (
NS 1888,
391 ;
BC 1888, 401;
CIL vi. 30876).
3 Certain antiquarians of the sixteenth
and fifteenth
centuries speak of an arcus Gordiani near the porta Chiusa
(for reff. see
HJ 390, n. 45;
LS i. 169;
BC 1913, 38), and this has been
connected
by some with architectural fragments found in the via
Gaeta and the
viale Castro Pretorio (BC 1872-3, 103, 233-237). One or
more such arches
may very probably have stood in or near the castra, but
there is no
evidence of an arch of Gordian, or that the fragments
discovered belonged
to that arch mentioned in the Renaissance (
BC 1913, 37-42). For further
discussion of the castra, see
Gilb. iii. 198-199; HJ 385-
390; LR 439-442
(the relief from an arch with a Victory is at Ny-Karlsberg,
No. 511);
for tabulae lusoriae found within it,
BC 1877, 81-100; for
inscribed
amphorae in the camp and vicinity,
BC 1879, 36-112, 143-
195;
1880,
82-117;
CIL xv. 4529-4898 passim). The latest study of
it is in
PBSx. 12-22 (by I. A. Richmond).
