See, for example, A Badawy, A History of Egyptian Architecture (Berkeley: Univ. of California Press, 1966), pp. 198–230; Ramsay MacMullen, Soldier and Civilian in the Later Roman Empire (Cambridge, MA: Harvard University Press, 1963). See also, Col. George Grogham, Army Life on the Western Frontier (Norman, OK: Univ. of Oklahoma Press, 1958).