Sentence:  He was thinking; but the glory of the song, the swell from the great organ, the clustered lights,nb..., the height and vastness of this noble fane, its antiquity and its strength—all these things seemed to have their <WSD>part</WSD> as causes of the thrilling emotion that accompanied his thoughts. 
Meaning of the word marked with <WSD> tags:  Position or role (especially in a play).