Sentence:  Again , Henley 's attitude of defiance which colors his <WSD>ideal</WSD> of self mastery is far from characteristic of a Stoic thinker like Marcus Aurelius , whose gentle acquiescence is almost Christian , comparable to the patience expressed in Milton 's sonnet on his own blindness . 
Meaning of the word marked with <WSD> tags:  the idea of something that is perfect; something that one hopes to attain