The Date of Pevensey and the Defense of an 'Imperium Britanniarum.'
Fulford, Michael, Tyers, Ian, Antiquity
New work at the late Roman fort at Pevensey has recovered oak foundation piles. The precision of a tree-ring date for them is occasion to look again at the pattern of coastal forts of which Pevensey is a part.
The late Roman forts, and their date The remains of the late Roman fort at Pevensey, East Sussex, are generally identified as those of Anderitum, one of the sites listed in the late 4th/early 5th-century Notitia Dignitatum as belonging to the litus Saxonicum under the command of a comes (count). The group of forts ranges from Brancaster (Branodunum), Norfolk to Pevensey, Sussex, and may include Portchester, Hampshire, if the latter is to be correctly equated with the name of Poltus Adurni, whose location is otherwise unidentified (White 1961; Johnson 1976; Johnston 1977; Mann 1989; Maxfield 1989) (Figure 1). All the forts listed in the Notitia Dignitatum except Brancaster and Reculver share to a varying extent the characteristics of late Roman military architecture, with walls of massive thickness (c. 3.3-4m at foundation level) lacking internal ramparts/banks, heavily fortified gates and rounded or D-shaped external towers for mounting artillery (Johnson 1983). In this respect they differ from Roman city walls in Britain which either, like Silchester, lacked external towers altogether or, as in the case of Caerwent, were thus provided with at a date after their original construction. Besides those coastal forts listed under the command of the comes litoris Saxonici in the Notitia Dignitatum, several others, including Bitterne at the head of Southampton Water, Cardiff at the head of Cardiff Bay and the confluence of several rivers, Caer Gybi, Holyhead, and Lancaster appear to have been built in the same late Roman military tradition (Johnson 1976: 132-54). Although they can be seen to be a subset of a larger group, it has been customary to begin any analysis of the role and function of the late Roman coastal forts with those that are listed in this late 4th/early 5th-century document, the Notitia Dignitatum, as under the command of the comes litoris Saxonici.
Until recently none of the British coastal forts was closely dated, but a combination of arguments based both on a study of the typology of the forts and on the date and frequency of the various coins recorded from the Saxon Shore fort group has produced a chronology for them which has found wide acceptance (Cunliffe 1968; Johnson 1976; Maxwell 1989). In this scheme Brancaster and Reculver, which both lack external towers and do possess internal ramparts, are dated to the early 3rd century, and thus the beginning of the series, while Burgh Castle, where only the upper sections of the external towers are bonded into the fortress wall proper, is seen as transitional. Richborough is thought to be marginally earlier than any of the others, and Johnson (1970; 1976) (contra Cunliffe 1968) has argued forcefully for a pre-carausian date, suggesting that the Emperor Probus may have been responsible for the initiative. At Dover, the late Roman fort which partly overlies the Classis Britannica fort has been provisionally dated to the late 3rd century (Philip 1981; Johnson 1989). On the south coast, Portchester and Pevensey provide examples of the late Roman defensive architecture at its most developed (Figure 2): Portchester has recently been dated by the find of a coin of Carausius in the construction levels to after 286 (Cunliffe 1975: 41), while Pevensey has been regarded as the latest of the group. The discovery of a coin of 330-35 in a void beneath one of the external towers supported the typological argument that Pevensey, with its irregular, oval plan dietated by the topography, was the last of the shore forts (Bushe-Fox 1932; Johnson 1989). At Bitterne, the most westerly of the forts on the south coast, re-examination of the coin evidence for the date of the defences suggests a late 3rd-century terminus post quem (King 1990).
The emphasis on a gradually evolving scheme of coastal defence, as put forward by Cunliffe (1968), tended to dispose of the idea, strongly propounded by D. …