Hannibal? He fought the Romans in Spain and then took the elephants over the Italian Alps and attacks Rome from the North. That is the greatest military feat for me.
The Romans used both north African elephants (now extinct) and Asian elephants which they got by long-distance trade.
Apparently the Asian elephants were larger; and besides I suppose India and Sri Lanka also had better infrastructure for catching and training war elephants than the Roman Empire did.
https://www.theguardian.com/science/2016/apr/03/where-muck-h...