Upvote:-1
The first Indian ruler to maintain a standing army was Bimbisara of the Haryanka Dynasty.
Upvote:2
I think during Alexander's period The great Nandha empire had the biggest army, consisting of 200,000 infantry, 20,000 cavalry, 2,000 war chariots and 3,000 war elephants (at the lowest estimates).
The king Pores, who was honored by Alexander the Great, was a king of marginal land inside the Nandha empire.
Probably Alexander the Great would have recorded his first loss in history, if he moved his forces a bit more inside the Nandha empire.