Ruler, white with age, back after conclusions of top church curia (7)
I believe the answer is:
pharaoh
'ruler' is the definition.
(Pharaoh is an example)
'age back after conclusions of top church curia' is the wordplay.
'age' becomes 'hoar' (I've seen this before**).
'back' says the letters should be written backwards.
'after' is a charade indicator (letters next to each other).
'conclusions of' indicates one should take the final letters.
The final letters of 'top church curia' are 'pha'.
'hoar' reversed gives 'raoh'.
'raoh' after 'pha' is 'PHARAOH'.
'white with' acts as a link.
This may not be correct. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for pharaoh that I've seen before include "Eg, Tutankhamen" , "Old Egyptian king" , "Royal ruler in ancient Egypt" , "Tut, in brief, was one" , "Former Egyptian ruler" .)