Time in history to muse (5)
I believe the answer is:
erato
'muse' is the definition.
(Erato is an example)
'time in history to' is the wordplay.
'time in history' becomes 'era'.
'era'+'to'='ERATO'
(Other definitions for erato that I've seen before include "daughter of Zeus" , "goddess" , "Greek muse - orate (anag)" , "verses she inspired" , "poetical inspiration" .)