I have a grammar question

When writing sentences which include titles such as ‘the captain’ are both words capitalised or is it just the noun? because I’ve been writing it as ‘the Captain’ and I cannot tell if its correct or not. Because The Captain looks weird mid-sentence and so does ‘the Captain’. 

Similarly, I have been referring to a group as ‘the Chosen’ - but is the determiner ‘the’ also capitalised or are neither words capitalised? 

Sorry if this makes no sense but its throwing me a loop.

I don’t think “the” is capitalized. (Unless it’s the first word of the sentence, obviously.) I’ve never seen “the” capitalized otherwise, though. So I think it’d be “the Captain.”