Type: Fort, Camp
|Possible Military Road: NNE (9) to Inchtvthil (Inchtuthil, Tayside)
Probable Military Road: NE (9) to Cargill (Tayside)
Gask Ridge: WSW (14) to Strageath
Gask Ridge: W (6) to Dvpplin
Possible Military Road: W (10) to Fendoch
NE (0.5) to Grassy Walls
SW (13) to Parknevk (Tayside)
SW (3.5) to Peel (Tayside)
First identified by Roy in the 18th century, this multi-period fort of some 9 acres (3.6 ha) lies at the confluence of the River Almond with the Tay and has suffered somewhat from the effects of erosion by the tributary stream during the intervening years. The north defences have been flattened by ploughing, measuring over 50 ft. across, while the southern rampart is still visible as a narrow rise in the ground.
The camp has not been fully excavated but a section across the north-western angle in 1973 revealed a ditch 11 ft. wide and 5½ ft. deep. (3.38 x 1.69 m), backed by a turf rampart averaging about 21 ft. (c.6.45 m) in width, and separated from it by an abnormally wide gap or 'berm' of over 30 ft. (c.9.4 m).
Current thought is that the camp was first built during the Flavian period, perhaps in the term of governor Sallustius Lucullus (c.85AD), to be briefly re-used during the later Antonine II period together with other forts at Ardoch and Strageath. It is possible, however, that, like the forts at Strageath and Carpow, the Bertha fort may have been re-occupied during the Severan campaigns of the early-3rd century.
There is one inscription on stone recorded in the R.I.B. for the Bertha fort (RIB 2213c; JRS xlix (1959), p.136-7, no.6), a religious dedicatory text, not an altarstone, which reads DISCIPVLINAE AVGVSTI "For the Discipline of the Emperor".
The only positively dateable pottery recovered from the Bertha fort is a single sherd of South Gaulish samian Form 15/17 or 18, which has been identified as Flavian, also other small pieces of Samian and coarseware tentatively dated to both to the Flavian and Antonine periods.