Chapter 48

           Langdoncouldscarcelybelievehisownsupposition,andyet,consideringwhohadgiventhisstonecylindertothem,howhehadgivenittothem,andnow,theinlaidRoseonthecontainer,Langdoncouldformulateonlyoneconclusion.

           IamholdingthePriorykeystone.

           Thelegendwasspecific.

           ThekeystoneisanencodedstonethatliesbeneaththesignoftheRose.

           «Robert?»Sophiewaswatchinghim.«What’sgoingon?»

           Langdonneededamomenttogatherhisthoughts.«Didyourgrandfathereverspeaktoyouofsomethingcalledlaclefdevoûte?»

           «Thekeytothevault?»Sophietranslated.

           «No,that’stheliteraltranslation.Clefdevoûteisacommonarchitecturalterm.Voûterefersnottoabankvault,buttoavaultinanarchway.Likeavaultedceiling.»

           «Butvaultedceilingsdon’thavekeys.»

           «Actuallytheydo.Everystonearchwayrequiresacentral,wedge-shapedstoneatthetopwhichlocksthepiecestogetherandcarriesalltheweight.Thisstoneis,inanarchitecturalsense,thekeytothevault.InEnglishwecallitakeystone.»Langdonwatchedhereyesforanysparkofrecognition.Sophieshrugged,glancingdownatthecryptex.«Butthisobviouslyisnotakeystone.»Langdondidn’tknowwheretobegin.Keystonesasamasonrytechniqueforbuildingstonearchwayshadbeenoneofthebest-keptsecretsoftheearlyMasonicbrotherhood.TheRoyalArchDegree.Architecture.Keystones.Itwasallinterconnected.