Religious alliance in turbulent age he and you'll put together (4,6)

'religious alliance' is the definition.
(alliance during the Crusades)

'turbulent age he and you'll put together' is the wordplay.
'turbulent' is an anagram indicator.
'and' is a charade indicator (letters next to each other).
'put together' is a charade indicator (letters next to each other).
'he' put next to 'youll' is 'heyoull'.
'age' after 'heyoull' is 'heyoullage'.
'heyoullage' is an anagram of 'HOLY LEAGUE'.

'in' acts as a link.