Calm once they had got themselves together (9)

I think it could be either:

Which length description are you looking for?:

5,5

collected

I'm a little stuck... Click here to teach me more about this clue!

'together' is the definition.
(thesaurus)

I can't explain the remainder of the clue.

(Other definitions for collected that I've seen before include "Came together" , "Gathered" , "Also cool and calm?" , "Brought together" , "composed" .)

I've seen this clue in the Evening Standard.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.