The Satavahana Empire did not exist at the time of Alexander's invasion. They rose after the fall of the Mauryan Empire. The three South Indian kingdoms of Cholas, Pandyas and Cheras were very old and they were contemporaries of the Mauryan Empire and older than the Mauryas. The three kingdoms lasted for fifteen or sixteen centuries after the fall of the Mauryas with occasional rises and declines. Among the three only the Cholas spread out of the confines of South India to spread their influence out into Southeast Asian countries like present day Myanmar, Malaysia, Indonesia etc.The Cholas had conquered the present day SriLanka and fought against the Srivijaya kingdom of Indonesian archipelago.The Cholas had a powerful navy.