TwelfthNight,OrWhatYouWillisacomedybyWilliamShakespeare,basedontheshortstory"OfApoloniusandSilla"aintitleisbelievedtobeanafterthought,createdafterJohnMarstonpremieredaplaytitledWhatYouWillduringthecourseofthewriting.
Illyria,thesettingofTwelfthNight,isimportanttotheplay'anancientregionontheeasterncoastoftheAdriaticSeacoveringpartsofmodernCroatia,MontenegroandAlbania,but,inthecontextofallegory,riaismentionedinoneofthesourceplaysforTwelfthNight,Plautus'sMenæchmi,asaplacewhere,asinTwelfthNight,espearehimselfmentioneditpreviously,inHenryVI,PartII,notingitsreputationforpirates.
LikemanyofShakespeare'scomedies,eadingcharacter,Viola,osescontactwithhertwinbrother,Sebastian,ngasamanandmasqueradingasayoungpageunderthenameCesario,noisinlovewiththebereavedLadyOlivia,whosebrotherhasrecentlydied,anddecidestouse"Cesario"ia,believingViolatobeaman,a,inturn,hasfalleninlovewiththeDuke,whoalsobelievesViolaisaman,andwhoregardsherashisconfidant.
WhenSebastianarrivesonthescene,akinghimforViola,Oliviaaskshimtomarryher,andtheyaresecretlybetrothed,lly,whenthetwinsappearinthepresenceofbothOliviaandtheDuke,thereismorewonderandaweattheirsimilarity,layendsinadeclarationofmarriagebetweentheDukeandViola,TobyandMaria,andOliviaandSebastian,thoughthemarriagesdonottakeplaceduringtheplay.
Scenefrom"TwelfthNight,"ActIIIbyFrancisWheatleyMuchoftheplayistakenupwiththecomicsubplot,inwhichseveralcharactersconspiretomakeOlivia'spompousheadsteward,Malvolio,volvesOlivia'suncle,SirTobyBelch;herwould-besuitor,asillysquirenamedSirAndrewAguecheek;herservantsMariaandFabian;andherf-ather'sfavoritefool,obyandSirAndrewdisturbthepeaceoftheirlady'shousebykeepinglatehoursandperpetuallysingingcatchesattheverytopoftheirvoices,isthebasisforSirToby,SirAndrew,andMaria'srevengeonMalvolio.
Maria,SirToby,SirAndrewAguecheekandcompanyconvinceMalvoliothatOliviaissecretlyinlovewithhim,andwritealetterinOlivia'shand,askingMalvoliotowearyellowstockingscross-gartered,berudetotherestoftheservants,ia,saddenedbyViola'sattitudetoher,asksforherchiefsteward,eaveshimtothecontrivancesofhistormentors.
PretendingthatMalvolioisinsane,heislockedupinaroom(acommon"treatment"forthementallyill),evisitshimtomockhis"insanity",oncedisguisedasthepriest,eendoftheplayMalvoliolearnsoftheirconspiracyandstormsoffpromisingrevenge,buttheDukedispatchessomeone(probablyFabian)topacifyhim.