Emperor had managed to cross India (7)
I believe the answer is:
hadrian
'emperor' is the definition.
(Roman emperor)
'had managed to cross india' is the wordplay.
'managed' becomes 'ran' (both can mean organised or was in charge of).
'to cross' indicates putting letters inside (some letters cross or go round others).
'india' becomes 'i' (phonetic alphabet: alpha, bravo, charlie etc.).
'ran' going around 'i' is 'rian'.
'had'+'rian'='HADRIAN'
(Other definitions for hadrian that I've seen before include "Roman emperor who visited Britain" , "Imperial wall-builder" , "Roman Emperor after Trajan" , "His wall crosses northern Britain" , "Roman emperor who built the British wall" .)