Settled close around fort (9)
I believe the answer is:
Here is my best explanation:
'settled' is the definition.
('ensconce' can be a synonym of 'settle')
'close around fort' is the wordplay.
'close' becomes 'end' (I've seen this before).
'around' indicates putting letters inside.
'fort' becomes 'sconce' (historical term for a fort or defence).
'end' enclosing 'sconce' is 'ENSCONCED'.