K orn ▁Fer ry ▁Tour ▁gradu ates ▁Category : G olf ers ▁from ▁Oklahoma ▁Category : Pe ople ▁from ▁Mid west ▁City , ▁Oklahoma ▁Category : 1 9 9 1 ▁birth s ▁Category : L iving ▁people <0x0A> </s> ▁The ▁Le iden ▁cho ir books ▁are ▁six ▁volumes ▁of ▁poly ph onic ▁r ena issance ▁music ▁of ▁the ▁Franco - F lem ish ▁school ▁copied ▁for ▁the ▁Piet ers ker k , ▁Le iden ▁and ▁now ▁preserved ▁at ▁the ▁Er f go ed ▁Le iden ▁en ▁Om stre ken ▁( former ly ▁Geme ent earch ief ▁Le iden ). ▁ ▁The ▁books ▁were ▁compiled ▁for ▁the ▁Piet ers ker k ' s ▁Ze ven - Get ij den col lege ▁( Col lege ▁of ▁the ▁Seven ▁Lit urg ical ▁H ours ), ▁a ▁professional ▁cho ir ▁employed ▁at ▁the ▁Piet ers ker k , ▁as ▁at ▁many ▁large ▁Dutch ▁parish ▁churches ▁during ▁the ▁ 1 5 th ▁and ▁ 1 6 th ▁Cent uries , ▁to ▁celebr ate ▁the ▁offici um ▁div in um ▁as ▁well ▁as ▁masses ▁for ▁the ▁dead ▁- ▁or ▁rather ▁those ▁of ▁the ▁dead ▁rich ▁enough ▁to ▁have ▁had ▁left ▁be quest s ▁and ▁end ow ments ▁for ▁masses ▁to ▁be ▁s ung ▁for ▁them . ▁Le iden ▁was ▁the ▁first ▁city ▁to ▁ac quire ▁a ▁professional ▁college ▁for ▁these ▁services , ▁c . 1 4 4 0 . ▁Rot ter dam , ▁Del ft ▁in ▁both ▁churches , ▁H aar lem , ▁G ou da , ▁Al k