ed ▁registry ▁only ▁became ▁of ▁significant ▁importance ▁in ▁modern ▁times . ▁ ▁Today , ▁the ▁standards ▁for ▁defining ▁and ▁registration ▁of ▁different ▁bre eds ▁vary . ▁Sometimes , ▁pure bre d ▁horses ▁are ▁called ▁Thor ough bre ds , ▁which ▁is ▁incorrect ; ▁" Th or ough bre d " ▁is ▁a ▁specific ▁bre ed ▁of ▁horse , ▁while ▁a ▁" p ure bre d " ▁is ▁a ▁horse ▁( or ▁any ▁other ▁animal ) ▁with ▁a ▁defined ▁pedig ree ▁recognized ▁by ▁a ▁bre ed ▁registry . ▁▁ ▁An ▁early ▁example ▁of ▁people ▁who ▁pract iced ▁select ive ▁horse ▁bre eding ▁were ▁the ▁Bed ou in , ▁who ▁had ▁a ▁reputation ▁for ▁careful ▁bre eding ▁practices , ▁keeping ▁extensive ▁pedig rees ▁of ▁their ▁Arab ian ▁horses ▁and ▁placing ▁great ▁value ▁upon ▁pure ▁blood lines . ▁Though ▁these ▁pedig rees ▁were ▁originally ▁transm itted ▁by ▁an ▁or al ▁tradition , ▁written ▁pedig rees ▁of ▁Arab ian ▁horses ▁can ▁be ▁found ▁that ▁date ▁to ▁the ▁ 1 4 th ▁century . ▁In ▁the ▁same ▁period ▁of ▁the ▁early ▁Renaissance , ▁the ▁Car th us ian ▁mon ks ▁of ▁southern ▁Spain ▁b red ▁horses ▁and ▁kept ▁met icul ous ▁pedig rees ▁of ▁the ▁best ▁blood stock ; ▁the ▁line age ▁surv ives ▁to ▁this ▁day ▁in ▁the ▁And alus ian ▁horse . ▁One ▁of ▁the ▁earliest ▁formal ▁reg ist ries ▁was ▁General ▁Stud ▁Book ▁for ▁Thor ough bre ds , ▁which ▁began ▁in ▁ 1 7 9 1 ▁and ▁trac ed ▁back ▁to ▁the ▁Arab ian