BLATOBULGIUM
(Birrens) Middlebie, Dumfriesshire, Scotland.
The site, mentioned in the
Antonine Itinerary, is ca. 2.4 km E of Ecclefechan, at the
junction of the Mein Water and the Middlebie Burn. The
visible fort, with rampart and ditches well preserved, is
of Antonine or mid 2d c. date.
The S part of the area had earlier been occupied by a
late 1st c. enclosure, constructed as a result of Agricola's
campaigns in Scotland. It was probably ca. 70 m square,
defended by a turf rampart and ditch. This enclosure was
directly succeeded by a fort of Hadrianic date (stratified
pottery). It had a turf rampart 6.7 m wide enclosing an
internal area of ca. 1.34 ha, one ditch on the N side, and
at least one ditch on the E and W sides. The S side has
been eroded by the Mein Water. Barrack blocks were of
timber, but the central block of buildings may have been
of stone. The Hadrianic fort faced S, and was apparently
an outpost fort to Hadrian's Wall. The inner of two
triple-ditched enclosures visible on air photographs in
the field W of the site was probably an annex.
The Hadrianic fort was leveled to make way for a new,
longer fort, presumably with a larger garrison or a
larger mounted contingent. The new fort (proved to be
Antonine by stratified coins and pottery) had its E and
W ramparts, and probably its S rampart, on approximately the same lines as the Hadrianic fort, but its N
rampart lay over 18 m N of the earlier one.
The longer, Antonine fort measured ca. 153 m N-S and
ca. 106 m E-W internally, an area of 1.6 ha. Its rampart
(the present visible one) was of turf, set on a stone base
5.4 m wide, with six ditches on the N side, and one
ditch at least on the E and W. In the interior a new central block of stone buildings was erected over the leveled
debris of Hadrianic structures, and N and S of the central
block were long narrow buildings also of stone, either
barracks or stables. Inscriptions show that the garrison
was the Cohors I Nervana of Germans, 1000 strong,
with a mounted contingent.
The Antonine fort, as first built, suffered serious damage, resulting in a layer of debris and burned material.
By A.D. 158, it had a new garrison, the Cohors II of
Tungrians, also 1000 strong, with a. mounted contingent.
No alteration was made in the dimensions, but extensive
repairs and rebuilding were needed in the interior. The
outer of the two triple-ditched enclosures in the field W
of the fort was probably an annex. Birrens, for a time
at least, formed part of the system supporting the Antonine Wall between Forth and Clyde.
None of the pottery found in the 1962-69 excavations
was later than the 2d c. A.D., but later Roman occupation
in the vicinity of the visible fort is proved by stray finds
of early 3d c. pottery from the bed of the Mein Water.
These may have come from one of the structures discovered by aerial photography N and S of the fort.
BIBLIOGRAPHY
Proc. Soc. Antiquaries of Scotland 30
(1896) 81-199; 72 (1938) 275-347; A. Robertson,
Birrens (
Blatobulgium) (1974).
A. S. ROBERTSON