The elder sort of English king (8)
I believe the answer is:
ethelred
'english king' is the definition.
'ethelred' can be an answer for 'king' (I've seen this before). I'm unsure of the 'english' bit.
'the elder sort' is the wordplay.
'sort' indicates an anagram.
'the'+'elder'='theelder'
'theelder' is an anagram of 'ETHELRED'.
'of' acts as a link.
Can you help me to learn more?
(Other definitions for ethelred that I've seen before include "English king between nine hundred and seventy-eight and ten hundred and sixteen" , "Unready monarch" , "King of England" , "Old king" , "English king from 978" .)