Old man respected is ruler restored (6)
I believe the answer is:
osiris
'old man respected is ruler restored' is the definition.
I can't judge whether this definition defines the answer.
'old man respected is ruler restored' is the wordplay.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'man respected' becomes 'si' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'ruler' becomes 'r' (r is abbreviation for rex).
'restored' indicates an anagram.
'is'+'r'='isr'
'isr' with letters rearranged gives 'ris'.
'o'+'si'+'ris'='OSIRIS'
Can you help me to learn more?
(Other definitions for osiris that I've seen before include "underworld boss" , "once highly esteemed by Egyptians" , "Egyptian god of the dead" , "one Egyptians worshipped" , "dead judge?" .)