Sentence:  That after all his years of effort to become a composer , he should now , <WSD>now</WSD> when he was still stoutly replying to the critics of his Discourse on the Arts and Sciences , be so close to a success in music and have to reject it . 
Meaning of the word marked with <WSD> tags:  in the historical present; at this point in the narration of a series of past events