Historians have often discussed the  three estates  of the Western world'nobility, church, and commons.
( Historians ( ( ( have often ) ( discussed ( ( the ( three estates ) ) ( of ( ( ( the ( Western ( world ( ` ( nobility ( , ( church , ) ) ) ) ) ) ) and ) commons ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Historians)) (VP (VBP have) (ADVP (RB often)) (VP (VBN discussed) (NP (NP (DT the) (CD three) (NNS estates)) (PP (IN of) (NP (NP (DT the) (JJ Western) (NN world) (`` `) (NN nobility) (, ,) (NN church) (, ,)) (CC and) (NP (NNS commons))))))) (. .)))
Historians have often discussed the one estate of the Western world, religion.
( Historians ( ( ( have often ) ( discussed ( ( the ( one estate ) ) ( of ( ( ( the ( Western world ) ) , ) religion ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Historians)) (VP (VBP have) (ADVP (RB often)) (VP (VBN discussed) (NP (NP (DT the) (CD one) (NN estate)) (PP (IN of) (NP (NP (DT the) (JJ Western) (NN world)) (, ,) (NP (NN religion))))))) (. .)))