Possible standard units of measurement in Roman military planning,' Britannia xii (1981), 13-36. 2 T.F.C. Blagg, 'Roman civil and military architecture in the province of Britain,' World Arch, xii (1980), 27-42. 3 The other ancient source which should perhaps be mentioned is pseudo-Hyginus, De munitionibus castmrum. The author of this treatise is, however, concerned with the rational deployment of prefabricated entities (i.e. tents), and his preoccupations cannot be expected to be those of the architect who was not primarily concerned with how many people could be fitted into a given space. 4 Vitruvius, De architectura I.praef. 2 ; I.iv.i. 5 G. Webster, The Roman Imperial Army (3rd edn, 1985), 158. 6 Vitruvius VII.praef. 10-18. 7 Thus Faventinus (//. c. A.D. 300); K. Plommer, Vitruvius and Later Roman Building Manuals (1973), introduction passim. A distinction should, however, be made between the principles upon which the design process was based, and the details through which the individual architect expressed himself, see T.F.C. Blagg, 'Reconstruction of Roman decorated architecture,' in P.J. Drury (ed.), Structural Reconstruction, BAR n o (1982). 131-52. 8 Walthew, op. cit. (note 1), 18.