Maintenance of leading medieval tower (6)

I believe the answer is:

upkeep

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'maintenance' is the definition.
(I know that maintenance can be written as upkeep)

'leading medieval tower' is the wordplay.
'leading' becomes 'up' (up can mean leading in a game).
'medieval tower' becomes 'keep' (I've seen this before. I am not sure about the 'medieval' bit.).
'up'+'keep'='UPKEEP'

'of' is the link.

Can you help me to learn more?

(Other definitions for upkeep that I've seen before include "Looking after" , "Cost of maintenance, say household" , "Cost of maintaining" , "Cost of support" , "Running costs" .)

I've seen this clue in The Independent.

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