Who's enemy finally denied in northern valley? (4)

I believe the answer is:

dale

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'northern valley?' is the definition.
(I've seen this before)

I cannot understand how the rest of the clue works.

(Other definitions for dale that I've seen before include "See 8" , "Open valley" , "An English valley" , "Up hill and down . . . ." , "Lead out of the river valley" .)

I've seen this clue in The Telegraph.

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