For a long time the Saxon Shore was regarded as being an entirely new creation of the 4th cent. ad. Seven of the listed units are new to the army of Britain as known in the principate (the Roman system of government 27 bc–ad 284). The appearance and style of the Saxon Shore forts themselves is new and different; they had high thick walls, massive rounded external towers, and more readily defensible secure gates. However, a closer examination of the evidence indicates continuity between the classis Britannica (the Roman fleet in the Channel) of the principate and the military dispositions discernible in the late empire. Archaeology has revealed an impressively large classis Britannica fort at Dover, and there is epigraphic evidence, in the form of stamped CL.BR tiles, for classis Britannica structures of the 2nd and 3rd cents. at Lympne, Portchester, and Pevensey. At Reculver there are archaeological indications of a 1st-cent. fortlet.
"Saxon Shore." The Oxford Companion to British History. . Encyclopedia.com. (February 18, 2018). http://www.encyclopedia.com/history/encyclopedias-almanacs-transcripts-and-maps/saxon-shore
"Saxon Shore." The Oxford Companion to British History. . Retrieved February 18, 2018 from Encyclopedia.com: http://www.encyclopedia.com/history/encyclopedias-almanacs-transcripts-and-maps/saxon-shore