Decrypt the following "secret" message by using frequency analysis?

Your "submission" must contain the key you discovered. (They key in the case of a substitution cipher is a particular permutation of the letters of the English alphabet.)

the cipher text given below

O sd ty tokpl s Enfnunmn; sfa dy gsdocy om hfn hg pln dhmp aompofeqomlna hg plsp kniqtcor. Dy sfrnmphkm lsa tnnf ghk dsfy ynskm rhqfmncchkm sfa myfaorm; sfa dy gsplnk lsa goccna mnunksc iqtcor mopqspohfm wopl lhfhqk sfa kniqpspohf. Ln wsm knminrpna ty scc wlh bfnw lod ghk lom ofpnekopy sfa ofangspoestcn sppnfpohf ph iqtcor tqmofnmm. Ln ismmna lom yhqfenk asym inkinpqsccy hrrqiona ty pln sggsokm hg lom rhqfpky; s uskonpy hg rokrqdmpsfrnm lsa iknunfpna lom dskkyofe nskcy, fhk wsm op qfpoc pln anrcofn hg cogn plsp ln tnrsdn s lqmtsfa sfa pln gsplnk hg s gsdocy. Sm pln rokrqdmpsfrnm hg lom dskkosen occqmpkspn lom rlsksrpnk, O rsffhp kngksof gkhd kncspofe plnd. Hfn hg lom dhmp ofpodspn gkonfam wsm s dnkrlsfp, wlh, gkhd s gchqkomlofe mpspn, gncc, plkhqel fqdnkhqm domrlsfrnm, ofph ihunkpy. Plom dsf, wlhmn fsdn wsm Tnsqghkp, wsm hg s ikhqa sfa qftnfaofe aomihmopohf, sfa rhqca fhp tnsk ph coun of ihunkpy sfa htcouohf of pln msdn rhqfpky wlnkn ln lsa ghkdnkcy tnnf aompofeqomlna ghk lom ksfb sfa dsefogornfrn. Lsuofe isoa lom antpm, plnknghkn, of pln dhmp lhfhqkstcn dsffnk, ln knpknspna wopl lom asqelpnk ph pln phwf hg Cqrnkfn, wlnkn ln couna qfbfhwf sfa of wknprlnafnmm. Dy gsplnk chuna Tnsqghkp wopl pln pkqnmp gkonfamloi, sfa wsm annicy ekonuna ty lom knpknsp of plnmn qfghkpqfspn rokrqdmpsfrnm. Ln toppnkcy anichkna pln gscmn ikoan wlorl cna lom gkonfa ph s rhfaqrp mh coppcn whkply hg pln sggnrpohf plsp qfopna plnd. Ln chmp fh podn of nfansuhqkofe ph mnnb lod hqp, wopl pln lhin hg inkmqsaofe lod ph tneof pln whkca sesof plkhqel lom rknaop sfa smmompsfrn. Tnsqghkp lsa psbnf nggnrpqsc dnsmqknm ph rhfrnsc lodmncg; sfa op wsm pnf dhfplm tnghkn dy gsplnk aomrhunkna lom sthan. Hunkvhyna sp plom aomrhunky, ln lsmpnfna ph pln lhqmn, wlorl wsm mopqspna of s dnsf mpknnp, fnsk pln Knqmm. Tqp wlnf ln nfpnkna, domnky sfa anmisok schfn wncrhdna lod. Tnsqghkp lsa msuna tqp s unky mdscc mqd hg dhfny gkhd pln wknrb hg lom ghkpqfnm; tqp op wsm mqggoronfp ph ikhuoan lod wopl mqmpnfsfrn ghk mhdn dhfplm, sfa of pln dnsfpodn ln lhina ph ikhrqkn mhdn knminrpstcn ndichydnfp of s dnkrlsfp'm lhqmn. Pln ofpnkusc wsm, rhfmnjqnfpcy, minfp of ofsrpohf; lom ekong hfcy tnrsdn dhkn anni sfa ksfbcofe wlnf ln lsa cnomqkn ghk kngcnrpohf; sfa sp cnfepl op phhb mh gsmp lhca hg lom dofa plsp sp pln nfa hg plknn dhfplm ln csy hf s tna hg morbfnmm, ofrsistcn hg sfy nxnkpohf. Lom asqelpnk sppnfana lod wopl pln eknspnmp pnfankfnmm; tqp mln msw wopl anmisok plsp plnok coppcn gqfa wsm ksioacy anrknsmofe, sfa plsp plnkn wsm fh hplnk ikhminrp hg mqiihkp. Tqp Rskhcofn Tnsqghkp ihmmnmmna s dofa hg sf qfrhddhf dhqca; sfa lnk rhqksen khmn ph mqiihkp lnk of lnk saunkmopy. Mln ikhrqkna icsof whkb; mln icsopna mpksw; sfa ty uskohqm dnsfm rhfpkouna ph nskf s ioppsfrn mrskrncy mqggoronfp ph mqiihkp cogn.