An ace involved with this medieval league (9)

I believe the answer is:

hanseatic

'medieval league' is the definition.
(the Hanseatic League - medieval merchant group)

'an ace involved with this' is the wordplay.
'involved with' indicates an anagram (involved can mean confusing or complex).
'an'+'ace'='anace'
'anace' anagrammed with 'this' gives 'HANSEATIC'.

(Another definition for hanseatic that I've seen is " medieval league".)

I've seen this clue in The Times.

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