theyarealsoacollectionofruleswhichhavebeengraduallydevelopedinawayhighlyfavourabletothepreservationofarchaicpeculiarities。Twocauseshavedonemosttoobscuretheoldestinstitutionsoftheportionofthehumanracetowhichwebelong：onehasbeentheformationthroughouttheWestofstrongcentralisedgovernments，concentratinginthemselvesthepublicforceofthecommunity，andenabledtogivetothatforceuponoccasionthespecialformoflegislativepower；theotherhasbeentheinfluence，directandindirect，oftheRomanEmpire，drawingwithitanactivityinlegislationunknowntothepartsoftheworldwhichwereneversubjectedtoit。Now，IrelandisallowedonallhandstohaveneverformedpartoftheEmpire；itwasveryslightlyaffectedfromadistancebytheImperiallaw；
and，evenifitbeadmittedthat，duringcertainintervalsofitsancienthistory，ithadacentralgovernment，assuredlythisgovernmentwasneverastrongone。UnderthesecircumstancesitisnotwonderfulthattheBrehonlaw，growingtogetherwithoutlegislationuponanoriginalbodyofAryancustom，andformedbeyondthelimitofthatcloudofRomanjuridicalideaswhichformanycenturiesoverspreadthewholeContinent，andevenatitsextremityextendedtoEngland，shouldpresentsomeverystronganalogiestoanothersetofderivativeAryanusages，theHindoolaw，whichwassimilarlydeveloped。Thecuriousandperplexingproblemswhichsuchamodeofgrowthsuggestshavetograppledwithbythestudentofeithersystem。
TheancientlawsofIrelandhavecomedowntousasanassemblageoflaw-tracts，eachtreatingofsomeonesubjectorofagroupofsubjects。Thevolumesofficiallytranslatedandpublishedcontainthetwolargestofthesetracts，theSenchusMor，orGreatBookoftheAncientLaw，andtheBookofAicill。
WhilethecomparisonoftheSenchusMorandoftheBookofAicillwithotherextantbodiesofarchaicrulesleavesnodoubtofthegreatantiquityofmuchoftheircontents，theactualperiodatwhichtheyassumedtheirpresentshapeisextremelyuncertain。MrWhitleyStokes，oneofthemosteminentoflivingCelticscholars，believes，uponconsiderationofitsverbalforms，thattheSenchusMorwascompiledinorperhapsslightlybeforetheeleventhcentury；andthereappearstobeinternalevidencewhichonthewholeallowsustoattributetheBookofAicilltothecenturypreceding。TheSenchusMor，itistrue，expresslyclaimsforitselfafarearlierorigin。Inaremarkablepreface，ofwhichIshallhavemuchtosayhereafter，itgivesanaccount，partlyinverse，ofthecircumstancesunderwhichitwasdrawnup，anditprofessestohavebeencompiledduringthelifeandunderthepersonalinfluenceofStPatrick。Thesepretensionshavebeeningeniouslysupported，butthereisnotmuchtemerity，Ithink，inrefusingtoacceptthefifthcenturyasthedateoftheSenchusMor。AtthesametimeitisfarfromimpossiblethatthewritingoftheancientIrishlawsbegansoonaftertheChristianisationofIreland。ItwasChristianity，a’religionofabook’，whichforthefirsttimeintroducedmanyoftherudernationsoutsidetheEmpiretotheartofwriting。WecannotsafelyclaimfortheChristianera，preciselythesamedegreeofculturewhichCaesarattributestotheCeltsoftheContinentinthefirstcenturybeforeChrist；but，evenifwecoulddoso，CaesarexpresslystatesoftheGaulsthat，thoughtheywereacquaintedwithwriting，theyhadsuperstitiousscruplesaboutusingwrittencharacterstopreserveanypartoftheirsacredliterature，inwhichtheirlawwouldthenbeincluded。Suchobjectionswould，however，necessarilydisappearwiththeconversionoftheIrishpeopletoChristianity。Onthewholethereisnoantecedentimprobabilityinthetraditionthat，soonafterthisconversion，theusagesoftheIrishbegantobestatedinwriting，andCelticscholarshavedetectednotalittleevidencethatpartsofthesemorevenerablewritingsareimbeddedinthetextoftheBookofAicillandoftheSenchusMor。
Itisextremelylikelythatthemostancientlawwaspreservedinrudeverseorrhythmicalprose。IntheoldestIrishtraditionsthelawyerisdistinguishedwithdifficultyfromthepoet，poetryfromliterature。BothintheSenchusMorandintheBookofAicilltheexpressstatementofthelawisdescribedas’castingathreadofpoetry’aboutit，andthetraditionalauthorsoftheSenchusMoraresaidtohaveexhibited’allthejudgementsandpoetryofthemenofErin。’ModernIrishscholarshiphas，infact，discoveredthatportionsoftheSenchusMorarereallyinverse。Thephenomenonisnotunfamiliar。MrGrote，speakingoftheElegiacsofSolon，andofthenaturalpriorityofversetoprose，saysHistoryofGreece，iii。119，’theacquisitionsaswellastheeffusionsofanintellectualman，eveninthesimplestform，thenadjustedthemselvesnottothelimitationsoftheperiodandsemicolon，buttothoseofthehexameterandpentameter。’Thereisnoquestion，Iconceive，thatthisancientwrittenverseiswhatisnowcalledasurvival，descendingtothefirstagesofwrittencompositionfromtheageswhenmeasuredrhythmwasabsolutelyessential，inorderthatthememorymightbearthevastburdensplaceduponit。ItisnowgenerallyagreedthatthevoluminousversifiedSanscritliterature，whichembracesnotonlythepoetryoftheHindoos，butmostoftheirreligion，muchofwhatstandstotheminplaceofhistory，andsomethingevenoftheirlaw，wasoriginallypreservedbyrecollectionandpublishedbyrecitation；andevennow，intheSanscritschoolswhichremain，thepupilistrainedtoexercisesofmemorywhicharelittleshortofthemiraculoustoanEnglishman。