andthebookofMaeswasplacedbytheolderChurchontheIndex。
ButaswenowlookbackovertheRevivalofLearning，theAgeofDiscovery，andtheReformation，wecanseeclearlythatpowerfulastheolderChurchthenwas，andpowerfulastheReformedChurchwastobe，therewasatworksomethingfarmoremightythaneitherorthanboth；andthiswasagreatlawofnature——thelawofevolutionthroughdifferentiation。Obedienttothislawtherenowbegantoarise，bothwithintheChurchandwithoutit，anewbodyofscholars——notsomuchtheologiansassearchersfortruthbyscientificmethods。Some，likeCusa，wereecclesiastics；some，likeValla，Erasmus，andtheScaligers，werenotsuchinanyrealsense；butwhetherinholyorders，really，nominally，ornotatall，theywere，firstofall，literaryandscientificinvestigators。
Duringthesixteenthcenturyastrongimpulsewasgiventomorethoroughresearchbyseveralveryremarkabletriumphsofthecriticalmethodasdevelopedbythisnewclassofmen，andtwooftheseoughtheretoreceiveattentiononaccountoftheirinfluenceuponthewholeaftercourseofhumanthought。
FormanycenturiestheDecretalsbearingthegreatnameofIsidorehadbeencherishedasamongthemostvaluedmunimentsoftheChurch。Theycontainedwhatclaimedtobeamassofcanons，lettersofpopes，decreesofcouncils，andthelike，fromthedaysoftheapostlesdowntotheeighthcentury——allsupportingatimportantpointsthedoctrine，thediscipline，theceremonial，andvarioushighclaimsoftheChurchanditshierarchy。
ButinthefifteenthcenturythatsturdyGermanthinker，CardinalNicholasofCusa，insistedonexaminingthesedocumentsandonapplyingtothemthesamethoroughresearchandpatientthoughtwhichledhim，evenbeforeCopernicus，todetecttheerrorofthePtolemaicastronomy。