JustatthetimethatMichaelMayerwasmakingknowntotheworldtheexistenceofsuchabodyastheRosicrucians，therewasborninItalyamanwhowasafterwardsdestinedtobecomethemostconspicuousmemberofthefraternity。ThealchymicmanianevercalledforththeingenuityofamoreconsummateormoresuccessfulimpostorthanJosephFrancisBorri。Hewasbornin1616accordingtosomeauthorities，andin1627accordingtoothers，atMilan；wherehisfather，theSignorBrandaBorri，practisedasaphysician。Attheageofsixteen，JosephwassenttofinishhiseducationattheJesuits’CollegeinRome，wherehedistinguishedhimselfbyhisextraordinarymemory。Helearnedeverythingtowhichheappliedhimselfwiththeutmostease。Inthemostvoluminousworksnofactwastoominuteforhisretention，andnostudywassoabstrusebutthathecouldmasterit；butanyadvantageshemighthavederivedfromthisfacility，wereneutralizedbyhisungovernablepassionsandhisloveofturmoilanddebauchery。Hewasinvolvedincontinualdifficulty，aswellwiththeheadsofthecollegeaswiththepoliceofRome，andacquiredsobadacharacterthatyearscouldnotremoveit。BytheaidofhisfriendsheestablishedhimselfasaphysicianinRome，andalsoobtainedsomesituationinthePope’shousehold。Inoneofhisfitsofstudiousnesshegrewenamouredofalchymy，anddeterminedtodevotehisenergiestothediscoveryofthephilosopher’sstone。Ofunfortunatepropensitieshehadquitesufficient，besidesthis，tobringhimtopoverty。Hispleasureswereasexpensiveashisstudies，andbothwereofanaturetodestroyhishealthandruinhisfairfame。Attheageofthirty-sevenhefoundthathecouldnotlivebythepracticeofmedicine，andbegantolookaboutforsomeotheremployment。Hebecame，in1653，privatesecretarytotheMarquisdiMirogli，theministeroftheArchdukeofInnsprukatthecourtofRome。Hecontinuedinthiscapacityfortwoyears；leading，however，thesameabandonedlifeasheretofore，frequentingthesocietyofgamesters，debauchees，andloosewomen，involvinghimselfindisgracefulstreetquarrels，andalienatingthepatronswhoweredesiroustobefriendhim。
Allatonceasuddenchangewasobservedinhisconduct。Theabandonedrakeputontheoutwardsedatenessofaphilosopher；thescoffingsinnerproclaimedthathehadforsakenhisevilways，andwouldlivethenceforthamodelofvirtue。Tohisfriendsthisreformationwasaspleasingasitwasunexpected；andBorrigaveobscurehintsthatithadbeenbroughtaboutbysomemiraculousmanifestationofasuperiorpower。Hepretendedthatheheldconversewithbeneficentspirits；thatthesecretsofGodandnaturewererevealedtohim；andthathehadobtainedpossessionofthephilosopher’sstone。Likehispredecessor，JacobBohmen，hemixedupreligiousquestionswithhisphilosophicaljargon，andtookmeasuresfordeclaringhimselfthefounderofanewsect。This，atRomeitself，andintheverypalaceofthePope，wasahazardousproceeding；andBorrijustawoketoasenseofitintimetosavehimselffromthedungeonsoftheCastleofSt。Angelo。HefledtoInnspruck，whereheremainedaboutayear，andthenreturnedtohisnativecityofMilan。
Thereputationofhisgreatsanctityhadgonebeforehim；andhefoundmanypersonsreadytoattachthemselvestohisfortunes。Allwhoweredesirousofenteringintothenewcommuniontookanoathofpoverty，andrelinquishedtheirpossessionsforthegeneralgoodofthefraternity。BorritoldthemthathehadreceivedfromthearchangelMichaelaheavenlysword，uponthehiltofwhichwereengraventhenamesofthesevencelestialIntelligences。“Whoevershallrefuse，“saidhe，“toenterintomynewsheepfold，shallbedestroyedbythepapalarmies，ofwhomGodhaspredestinedmetobethechief。Tothosewhofollowme，alljoyshallbegranted。Ishallsoonbringmychemicalstudiestoahappyconclusionbythediscoveryofthephilosopher’sstone，andbythismeansweshallallhaveasmuchgoldaswedesire。Iamassuredoftheaidoftheangelichosts，andmoreespeciallyofthearchangelMichael’s。WhenIbegantowalkinthewayofthespirit，Ihadavisionofthenight，andwasassuredbyanangelicvoicethatIshouldbecomeaprophet。InsignofitI
sawapalm-tree，surroundedwithallthegloryofParadise。TheangelscometomewheneverIcall，andrevealtomeallthesecretsoftheuniverse。Thesylphsandelementaryspiritsobeyme，andflytotheuttermostendsoftheworldtoserveme，andthosewhomIdelighttohonour。“Byforceofcontinuallyrepeatingsuchstoriesasthese，Borrisoonfoundhimselfattheheadofaveryconsiderablenumberofadherents。Ashefiguresinthesepagesasanalchymist，andnotasareligioussectarian，itwillbeunnecessarytorepeatthedoctrineswhichhetaughtwithregardtosomeofthedogmasoftheChurchofRome，andwhichexposedhimtothefierceresentmentofthepapalauthority。Theyweretothefullasridiculousashisphilosophicalpretensions。Asthenumberofhisfollowersincreased，heappearstohavecherishedtheideaofbecomingonedayanewMahomet，andoffounding，inhisnativecityofMilan，amonarchyandreligionofwhichheshouldbethekingandtheprophet。Hehadtakenmeasures，intheyear1658，forseizingtheguardsatallthegatesofthatcity，andformallydeclaringhimselfthemonarchoftheMilanese。Justashethoughttheplanripeforexecution，itwasdiscovered。Twentyofhisfollowerswerearrested，andhehimselfmanaged，withtheutmostdifficulty，toescapetotheneutralterritoryofSwitzerland，wherethepapaldispleasurecouldnotreachhim。
Thetrialofhisfollowerscommencedforthwith，andthewholeofthemweresentencedtovarioustermsofimprisonment。Borri’strialproceededinhisabsence，andlastedforupwardsoftwoyears。Hewascondemnedtodeathasahereticandsorcererin1661，andwasburnedineffigyinRomebythecommonhangman。