Old mathematician rang, interrupting warlord (10)
I believe the answer is:
archimedes
'old mathematician' is the definition.
(ancient Greek mathematician)
'rang interrupting warlord' is the wordplay.
'rang' becomes 'chimed' (I've seen this in another clue).
'interrupting' is an insertion indicator.
'warlord' becomes 'ares' (I can't explain this - if you can you should give a lot more credence to this answer).
'chimed' put into 'ares' is 'ARCHIMEDES'.
Can you help me to learn more?
(Other definitions for archimedes that I've seen before include "Greek physicist" , "'Eureka' scientist" , "Old mathematician" , "Syracusan" , "Ancient Greek mathematician/inventor" .)