Question 2: Which one is the correct sentence construction: ''to believe someone/something'' or ''to believe in someone/something''? (I always get confused as to whether I should add the ''in'' or not) They have different meanings: 2a - "to believe someone/something" = "to believe that what someone says is true" / "to believe that something is true" Examples: - John said Joe took the book, but Joe denies it. - I believe John. (= I believe that what John said is true.) - People say that Vikings reached Canada about 1000 AD. - I believe it. (= I believe that Vikings reached Canada about 1000 AD.) 2b) "to believe in someone" = "to believe that someone is trustworthy." - John wants to borrow money from me. - I believe in John. (= I believe he is trustworthy.)

1) It is definitely archaic if you are referring to American English. You will only read this kind of English in books. As for other regions, it may still be used. Other examples of words/grammar aren't used often in the US but are still used in other countries or special regions: ought shall whom

Question 1 it's not archaic, but it has always been unusual, and it reads slightly awkwardly, perhaps because it resembles and might be confused with the form Chris listed as 2a. I would have used 'believed to be' to make things clearer, also 'thought to be', 'considered to be' etc.