180 The Imperial Government
existenceofsimultaneousthreatstotheEmpireonseveralfrontswhichin-
ducedConstantiustoappointhiscousinJulianasCaesarin355andsendhim
toGaul.^88
Ithadalreadybeenestablishedlongbeforethatanemperor,onceincom-
mandonaparticularfront,tookdirecttacticalandstrategiccommandofit,
fightingbattlesanddeterminingthegeographicalandphysicalcharacterof
frontierinstallations.Forinstance,weoweouronlypreciseliteraryreference
tothepushingforwardoftheGermanfrontierin83toFrontinus:^89
Imperator Caesar Domitianus Augustus—when the Germans, in ac-
cordancewiththeirusualcustom,keptemergingfromwoodlandpas-
turesandunsuspectedhidingplacestoattackourmenandthenfinding
asaferefugeinthedepthsoftheforest—by(constructing)limitesalong
a stretch of one hundred twenty miles, not onlychanged the nature
ofthewar,butbroughthisenemiesbeneathhissway,byuncovering
theirhidingplaces.ThequestionofwhetherhemeanstosaythatDomitiandroveroadsdirectly
intoenemyterritory^90 orconstructedlimites(roads)laterallyoveradistance
of120miles^91 isnotassignificantforpresentpurposesasthefactthatFronti-
nusrepresentsthisasastrategicchoicemadebytheEmperorinperson.He
similarlyattributestoDomitianchoicesofothersorts:therusebywhichhe
setoutfromRomeonthepretenceofconductingacensusinGaul;atactical
deviceusedinbattleagainsttheChatti;andthepaymentofcompensationfor
landonwhichcastella(forts)werebuiltduringthewar.^92 Again,togiveonly
isolatedexamples,theHistoria AugustaattributestothemomentofHadrian’s
visittoBritainin121/2hisbuildingoftheWall‘‘toseparatethebarbarians
andtheRomans.’’^93 DiodescribesCaracallaseeingtothesitingoffortsand
settlementsonhisGermancampaignof213,^94 whileAmmianusmentionsthe
fortification of Circesium by Diocletian and details the major programme
ofmilitaryconstructionalongtheRhineundertakenbyValentinianin369
onwards.^95 J.J.Wilkeshasdrawnattentiontothefactthatinscriptionsin-
- Zosimus3,1.
89.Strat.1,3,10. - SoR.Syme,CAHXI(1936),162–63.
- SoH.Schoenberger,JRS59(1969):159.
92.Strat.1,1,8;2,3,23;2,11,7.
93.V. Had.11,2. - 77,13,4(388–89).
- Circesium:Ammianus22,5,2.Rhine:28,2,1–6,cf.30,7,6.SeeH.Schoenberger,
JRS69(1969):182–86.