ButifLessing’stheologymustbeconsideredimperfect，itisnonethelessadmirableasfarasitgoes。Withitspeculiardoctrinesofloveandfaith，itteachesamoralityfarhigherthananythatPuritanismeverdreamedof。Andwithitstheoryofdevelopmentitcutsawayeverypossiblelogicalbasisforintolerance。ItisthistheologytowhichLessinghasgivenconcreteexpressioninhisimmortalpoemof“Nathan。“
Thecentralideaof“Nathan“wassuggestedtoLessingbyBoccaccio’sstoryof“TheThreeRings，“whichissupposedtohavehadaJewishorigin。Saladin，pretendingtobeinspiredbyasudden，imperiouswhim，suchasis“notunbecominginaSultan，“
demandsthatNathanshallanswerhimonthespurofthemomentwhichofthethreegreatreligionsthenknown——Judaism，Mohammedanism，Christianity——isadjudgedbyreasontobethetrueone。Foramomentthephilosopherisinaquandary。Ifhedoesnotpronounceinfavourofhisownreligion，Judaism，hestultifieshimself；butifhedoesnotawardtheprecedencetoMohammedanism，hewillapparentlyinsulthissovereign。WithtrueOrientaltactheescapesfromthedilemmabymeansofaparable。
Therewasonceaman，saysNathan，whopossessedaringofinestimablevalue。Notonlywasthestonewhichitcontainedincomparablyfine，butitpossessedthemarvellouspropertyofrenderingitsowneragreeablebothtoGodandtomen。Theoldmanbequeathedthisringtothatoneofhissonswhomhelovedthemost；andtheson，inturn，madeasimilardispositionofit。Sothat，passingfromhandtohand，theringfinallycameintothepossessionofafatherwholovedhisthreesonsequallywell。
Untowhichoneshouldheleaveit？Togetridoftheperplexity，hehadtwootherringsmadebyajeweller，exactlyliketheoriginal，andtoeachofhisthreesonshebequeathedone。Eachthenthinkingthathehadobtainedthetruetalisman，theybeganviolentlytoquarrel，andafterlongcontentionagreedtocarrytheirdisputebeforethejudge。Butthejudgesaid:“Quarrelsomefellows！Youareallthreeofyoucheatedcheats。Yourthreeringsarealikecounterfeit。Forthegenuineringislost，andtoconcealtheloss，yourfatherhadmadethesethreesubstitutes。“