Legendary cycle tour marred, the crashes after line (2,5,7)
I believe the answer is:
le morte darthur
'legendary cycle' is the definition.
(I've seen this before)
'tour marred the crashes after line' is the wordplay.
'crashes' indicates anagramming the letters.
'after' says to put letters next to each other.
'line' becomes 'l' (used when specifying particular lines from a poem).
'tour'+'marred'+'the'='tourmarredthe'
'tourmarredthe' with letters rearranged gives 'emortedarthur'.
'emortedarthur' put after 'l' is 'LE MORTE DARTHUR'.
(Another definition for le morte darthur that I've seen is " legendary cycle".)