Revived a festival introduced by Magritte and Dali, originally (10)
I believe the answer is:
reawakened
'revived' is the definition.
(I've seen this before)
'a festival introduced by magritte and dali originally' is the wordplay.
'festival' becomes 'wake'.
'introduced by' indicates putting letters inside (I've seen this in other clues).
'magritte' becomes 'rene' (Rene Magritte).
'and' says to put letters next to each other.
'originally' suggests taking the first letters.
The initial letter of 'dali' is 'd'.
'a'+'wake'='awake'
'awake' put within 'rene' is 'reawakene'.
'reawakene'+'d'='REAWAKENED'
(Other definitions for reawakened that I've seen before include "stirred up afresh" , "Revived" , "Roused again" .)