Inspiteofalltheseopposingforces，theevolutionofmedicalsciencecontinued，thoughbutslowly。InthesecondcenturyoftheChristianeraGalenhadmadehimselfagreatauthorityatRome，andfromRomehadswayedthemedicalscienceoftheworld：
hisgeniustriumphedoverthedefectsofhismethod；but，thoughhegaveapowerfulimpulsetomedicine，hisdogmatismstoodinitswaylongafterward。
Theplaceswheremedicine，suchasitthusbecame，couldbeapplied，wereatfirstmainlytheinfirmariesofvariousmonasteries，especiallythelargeronesoftheBenedictineorder：
thesewerefrequentlydevelopedintohospitals。Manymonksdevotedthemselvestosuchmedicalstudiesaswerepermitted，andsundrychurchmenandlaymendidmuchtosecureandpreservecopiesofancientmedicaltreatises。So，too，inthecathedralschoolsestablishedbyCharlemagneandothers，provisionwasgenerallymadeformedicalteaching；butallthisinstruction，whetherinconventsorschools，waswretchedlypoor。ItconsistednotindevelopingbyindividualthoughtandexperimentthegiftsofHippocrates，Aristotle，andGalen，butalmostentirelyintheparrot-likerepetitionoftheirwritings。
But，whiletheinheritedideasofChurchleaderswerethusunfavourabletoanyproperdevelopmentofmedicalscience，thereweretwobodiesofmenoutsidetheChurchwho，thoughlargelyfetteredbysuperstition，werefarlesssothanthemonksandstudentsofecclesiasticalschools：theseweretheJewsandMohammedans。Thefirstoftheseespeciallyhadinheritedmanyusefulsanitaryandhygienicideas，whichhadprobablybeenfirstevolvedbytheEgyptians，andfromthemtransmittedtothemodernworldmainlythroughthesacredbooksattributedtoMoses。