Answer:
Hi! I wish we had more information about where is this excerpt from, who is the author, etc. in order to make a better interpretation of it. Anyways, I'll try to help you by giving you the best answer possible with the facts we have here.
Explanation:
The task is asking for an explanation on the matter, so I would say, after carefully reading these lines, that the matter here is that this man, the captain of "<em>a bawbling vessel</em>" <u>was different from who he used to be, according to the speaker.</u> <em>He was "darker", something had changed him</em>, some situation that we don't know of, that is not described in the excerpt changed him for good, a "<em>loss</em>" that "<em>cried fame and honour on him</em>".
It is very difficult to understand what happened exactly, but we can see that this man is damaged and has become a dark soul.
Hope this helps!