PartV。
IfweextendourviewfromthetropictothemouthoftheTanais，wemayobserve，ononehand，theprecautionsofJustiniantocurbthesavagesofAethiopia，^125andontheother，thelongwallswhichheconstructedinCrimaeafortheprotectionofhisfriendlyGoths，acolonyofthreethousandshepherdsandwarriors。^126FromthatpeninsulatoTrebizond，theeasterncurveoftheEuxinewassecuredbyforts，byalliance，orbyreligion；andthepossessionofLazica，theColchosofancient，theMingreliaofmodern，geography，soonbecametheobjectofanimportantwar。Trebizond，inafter—timestheseatofaromanticempire，wasindebtedtotheliberalityofJustinianforachurch，anaqueduct，andacastle，whoseditchesarehewninthesolidrock。Fromthatmaritimecity，frontierlineoffivehundredmilesmaybedrawntothefortressofCircesium，thelastRomanstationontheEuphrates。^127AboveTrebizondimmediately，andfivedays\'journeytothesouth，thecountryrisesintodarkforestsandcraggymountains，assavagethoughnotsoloftyastheAlpsandthePyrenees。Inthisrigorousclimate，^128wherethesnowsseldommelt，thefruitsaretardyandtasteless，evenhoneyispoisonous:themostindustrioustillagewouldbeconfinedtosomepleasantvalleys；andthepastoraltribesobtainedascantysustenancefromthefleshandmilkoftheircattle。TheChalybians^129derivedtheirnameandtemperfromtheironqualityofthesoil；and，sincethedaysofCyrus，theymightproduce，underthevariousappellationsofChadaeansandZanians，anuninterruptedprescriptionofwarandrapine。UnderthereignofJustinian，theyacknowledgedthegodandtheemperoroftheRomans，andsevenfortresseswerebuiltinthemostaccessiblepassages，toexcludetheambitionofthePersianmonarch。^130TheprincipalsourceoftheEuphratesdescendsfromtheChalybianmountains，andseemstoflowtowardsthewestandtheEuxine:bendingtothesouth—west，theriverpassesunderthewallsofSatalaandMelitene，whichwererestoredbyJustinianasthebulwarksoftheLesserArmenia，andgraduallyapproachestheMediterraneanSea；tillatlength，repelledbyMountTaurus，^131theEuphratesinclinesitslongandflexiblecoursetothesouth—eastandtheGulfofPersia。AmongtheRomancitiesbeyondtheEuphrates，wedistinguishtworecentfoundations，whichwerenamedfromTheodosius，andtherelicsofthemartyrs；andtwocapitals，AmidaandEdessa，whicharecelebratedinthehistoryofeveryage。TheirstrengthwasproportionedbyJustiniantothedangeroftheirsituation。AditchandpalisademightbesufficienttoresisttheartlessforceofthecavalryofScythia；
butmoreelaborateworkswererequiredtosustainaregularsiegeagainstthearmsandtreasuresofthegreatking。Hisskilfulengineersunderstoodthemethodsofconductingdeepmines，andofraisingplatformstotheleveloftherampart:heshookthestrongestbattlementswithhismilitaryengines，andsometimesadvancedtotheassaultwithalineofmovableturretsonthebacksofelephants。InthegreatcitiesoftheEast，thedisadvantageofspace，perhapsofposition，wascompensatedbythezealofthepeople，whosecondedthegarrisoninthedefenceoftheircountryandreligion；andthefabulouspromiseoftheSonofGod，thatEdessashouldneverbetaken，filledthecitizenswithvaliantconfidence，andchilledthebesiegerswithdoubtanddismay。^132ThesubordinatetownsofArmeniaandMesopotamiawerediligentlystrengthened，andthepostswhichappearedtohaveanycommandofgroundorwaterwereoccupiedbynumerousforts，substantiallybuiltofstone，ormorehastilyerectedwiththeobviousmaterialsofearthandbrick。TheeyeofJustinianinvestigatedeveryspot；andhiscruelprecautionsmightattractthewarintosomelonelyvale，whosepeacefulnatives，connectedbytradeandmarriage，wereignorantofnationaldiscordandthequarrelsofprinces。WestwardoftheEuphrates，asandydesertextendsabovesixhundredmilestotheRedSea。Naturehadinterposedavacantsolitudebetweentheambitionoftworivalempires；theArabians，tillMahometarose，wereformidableonlyasrobbers；andintheproudsecurityofpeacethefortificationsofSyriawereneglectedonthemostvulnerableside。
[Footnote125:SeeProcopius，Persic。l。i。c。19。Thealtarofnationalconcern，ofannualsacrificeandoaths，whichDiocletianhadcreatedintheIslaofElephantine，wasdemolishedbyJustinianwithlesspolicythan]
[Footnote126:ProcopiusdeEdificiis，l。iii。c。7。Hist。l。