English fighting over Germany to get daughter to an old king (6)
I believe the answer is:
edward
'an old king' is the definition.
(any of several kings called Edward)
'english fighting over germany to get daughter' is the wordplay.
'english' becomes 'E' (abbreviation).
'fighting' becomes 'war'.
'over germany' becomes 'd' (international vehicle registration code. I am not sure about the 'over' bit.).
'to get' means one lot of letters go next to another.
'daughter' becomes 'd'.
'war'+'d'='ward'
'ward' after 'd' is 'dward'.
'e'+'dward'='EDWARD'
'to' is the link.
(Other definitions for edward that I've seen before include "Ted" , "-- Lear; -- Heath" , "The Black Prince's name" , "-- Lear, poet" , "King who abdicated" .)