The Mahajanapadas and the Rise of Magadha

Buddhist and Jain texts list sixteen mahajanapadas — great territorial states — from Gandhara and Kamboja in the north-west to Anga on the Bay of Bengal. This era is called India's second urbanisation: fortified towns, punch-marked silver coins, a money economy, craft guilds and long-distance trade all appear together in the Ganga plains.

The states were of two political types. Most were monarchies growing into kingdoms; but some — the Vrijji confederacy with its capital at Vaishali, the Mallas of Kushinara and Pava, the Shakyas of Kapilavastu — were gana-sanghas, oligarchic republics where heads of leading families debated and voted in assembly halls. These republics are a precious record of early republican government in world history.

Among the rivals — Kosala, Vatsa, Avanti and Magadha — Magadha prevailed. Its advantages were decisive: rich alluvial farmland, inexhaustible timber, iron ore from the Rajgir hills that armed its soldiers and elephants, control of Ganga river trade, and an unusually ambitious line of kings who were aided by an early use of war elephants on a large scale.

The Haryanka dynasty made the first push: Bimbisara (c. 544–492 BCE) expanded by marriage and war, and his son Ajatashatru conquered Vaishali and Kosala. The capital moved from Rajagriha to the fortress town of Pataliputra. The Shishunagas absorbed Avanti; the Nandas under Mahapadma — remembered as a ruler of Shudra origin who uprooted the old Kshatriya lineages — built the largest army and the heaviest taxation the age had known, and passed the kingdom almost intact to the Mauryas.

Even as Magadha rose, the north-west passed under foreign eyes: Cyrus and Darius of Persia annexed the Indus lands, the richest satrapy of the Achaemenid empire, and in 326 BCE Alexander of Macedon crossed the Hindu Kush. At the Hydaspes (Jhelum) Alexander defeated the brave king Porus, but his exhausted army refused to march beyond the Beas against the Nandas, and he turned back, leaving Satraps who collapsed within years. The invasion's deepest consequence was indirect: it opened roads between India and the Hellenistic world, and cleared the north-west for Chandragupta Maurya.