Political activity in the 6th–5th century bce centerd on the control of the Ganges valley. The states of Kashi, Koshala, and Magadha and the Vrijjis battled for this control for a century until Magadha emerged victorious. Magadha’s success was partly due to the political ambition of its king, Bimbisara (c. 543–491 bce). He conquered Anga, which gave him access to the Ganges delta—a valuable asset in terms of the nascent maritime trade. Bimbisara’s son Ajatashatru—who achieved the throne through patricide—implemented his father’s intentions within about 30 years. Ajatashatru strengthened the defenses of the Magadhan capital, Rajagrha, and built a small fort on the Ganges at Pataligrama, which was to become the famous capital Pataliputra (modern Patna). He then attacked and annexed Kashi and Koshala. He still had to subdue the confederacy of the Vrijji state, and this turned out to be a protracted affair lasting 16 years. Ultimately the Vrijjis, including the important Licchavi clan, were overthrown, having been weakened by a minister of Ajatashatru, who was able to sow dissension in the confederacy.

The success of Magadha was not solely attributable to the ambition of Bimbisara and Ajatashatru. Magadha had an excellent geographic location controlling the lower Ganges and thus drew revenue from both the fertile plain and the river trade. Access to the delta also brought in lucrative profits from the eastern coastal trade. Neighbouring forests provided timber for building and elephants for the army. Above all, nearby rich deposits of iron ore gave Magadha a lead in technology.

Bimbisara had been one of the earliest Indian kings to emphasize efficient administration, and the beginnings of an administrative system took root. Rudimentary notions of land revenue developed. Each village had a headman who was responsible for collecting taxes and another set of officials who supervised the collection and conveyed the revenue to the royal treasury. But the full understanding of the utilization of land revenue as a major source of state income was yet to come. The clearing of land continued apace, but it is likely that the agrarian settlements were small, because literary references to journeys from one town to another mention long stretches of forest paths.

After the death of Ajatashatru (c. 459 bce) and a series of ineffectual rulers, Shaishunaga founded a new dynasty (see Shaishunaga dynasty), which lasted for about half a century until ousted by Mahapadma Nanda. The Nandas are universally described as being of low origin, perhaps Sudras. Despite these rapid dynastic changes, Magadha retained its position of strength. The Nandas continued the earlier policy of expansion. They are proverbially connected with wealth, probably because they realized the importance of regular collections of land revenue.

Campaigns of Alexander the Great

The northwestern part of India witnessed the military campaign of Alexander the Great of Macedon, who in 327 bce, in pursuing his campaign to the eastern extremities of the Achaemenian Empire, entered Gandhara. He campaigned successfully across the Punjab as far as the Beas River, where his troops refused to continue fighting. The vast army of the Nandas is referred to in Greek sources, and some historians have suggested that Alexander’s Macedonian and Greek soldiers may have mutinied out of fear of this army. The campaign of Alexander made no impression on the Indian mind, for there are no references to it in Indian sources. A significant outcome of his campaign was that some of his Greek companions—such as Onesicritus, Aristobulus, and his admiral, Nearchus—recorded their impressions of India. Later Greek and Roman authors such as Strabo and Arrian, as well as Pliny and Plutarch, incorporated much of this material into their writings. However, some of the accounts are fanciful and make for better fiction than history. Alexander established a number of Greek settlements, which provided an impetus for the development of trade and communication with western Asia. Most valuable to historians was a reference to Alexander’s meeting the young prince Sandrocottos, a name identified in the 18th century as Chandragupta, which provides a chronological landmark in early Indian history.

Chandragupta Maurya

Chandragupta overthrew the Nanda power in Magadha and then campaigned in central and northern India. Greek sources report that he engaged in a conflict in 305 bce in the trans-Indus region with Seleucus I Nicator, one of Alexander’s generals, who, following the death of Alexander, had founded the Seleucid dynasty in Iran. The result was a treaty by which Seleucus ceded the trans-Indus provinces to the Maurya and the latter presented him with 500 elephants. A marriage alliance is mentioned, but no details are recorded.

The treaty ushered in an era of friendly relations between the Mauryas and the Seleucids, with exchanges of envoys. One among them, the Greek historian Megasthenes, left his observations in the form of a book, the Indica. Although the original has been lost, extensive quotations from it survive in the works of the later Greek writers Strabo, Diodorus, and Arrian. A major treatise on political economy in Sanskrit is the Artha-shastra of Kautilya (or Canakya, as he is sometimes called). Kautilya, it is believed, was prime minister to Chandragupta, although this view has been contested. In describing an ideal government, Kautilya indicates contemporary assumptions of political and economic theory, and the description of the functioning of government occasionally tallies with present-day knowledge of actual conditions derived from other sources. The date of origin of the Artha-shastra remains problematic, with suggested dates ranging from the 4th century bce to the 3rd century ce. Most authorities agree that the kernel of the book was originally written during the early Mauryan period but that much of the existing text is post-Mauryan.

According to Jain sources, Chandragupta became a Jain toward the end of his reign. He abdicated in favor of his son Bindusara, became an ascetic, and traveled with a group of Jain monks to southern India, where he died, in the orthodox Jain manner, by deliberate slow starvation.

Bindusara

The second Mauryan emperor was Bindusara, who came to the throne about 297 bce. Greek sources refer to him as Amitrochates, the Greek for the Sanskrit amitraghata, “destroyer of foes.” This name perhaps reflects a successful campaign in the Deccan, Chandragupta having already conquered northern India. Bindusara’s campaign stopped in the vicinity of Karnataka, probably because the territories of the extreme south, such as those of the Colas, Pandyas, and Ceras, were well-disposed in their relations toward the Mauryas.