Chandragupta Maurya (340 BC - 298 BC) was the founder of the Mauryan Empire and the first emperor to unify India into one state. Chandragupta Maurya is a pivotal figure in the history of India. After unifying India, Chandragupta and his chief advisor Chankaya passed a series of major economic and political reforms. Chandragupta's reign was a time of great social and religious reform in India. Chandragupta Maurya, with the help of Chankaya, defeated the Magadha king and the army of the Chandravanshi clan. Following his victory, the defeated generals of Alexander settled in Gandhara (the Kamboja kingdom), today's Afghanistan. Parvateshwara (Porus), a king of Punjab, was the only local king who was able to challenge Alexander at the Battle of the Hydaspes River, but he was defeated. Chanakaya then went further east to Magadha, to seek the help of Dhana Nanda, who ruled the vast Nanda Empire which extended from Bihar and Bengal in the east to Punjab and Sindh in the west, but Dhana Nanda refused to help him. After this incident, Chankaya began to persuade his disciple Chandragupta of the need to build an empire that could protect Indian territories from foreign invasion.