Nanda Empire
The Nanda Empire is recognized for forming the first true empire in South Asia, and did so by maintaining a large standing army. According to Pliny the Elder, the Nanda Empire employed 200,000 infantry, 20,000 cavalry, 3,000 elephants, and 2,000 chariots at their peak. The Maurya Empire overthrew the Nanda Empire, and formed the largest standing army of its time. They initially relied on multiethnic mercenaries and eventually formed a large professional army of 600,000 infantry, 30,000 cavalry, and 9,000 elephants according to Pliny. During the Maurya Empire, Chanakya detailed the branches and roles of the standing army in his work Arthashastra. According to the Arthashastra, recruitment into the Mauryan army wasn't strictly reserved for the kshatriya class as in the past, and employed people of all communities.