in 330 BCE, and the stiff resistance that they had met in north-western India in the subsequent years had demoralised them. They mutinied, when faced with the prospect of facing the Nanda army, forcing Alexander to withdraw from India. Administration Little information survives on the Nanda administration today. The Puranas describe the Nanda king as ekarat ("single ruler"), which suggests that the Nanda empire was an integrated monarchy rather than a group of virtually independent feudal states. However, the Greek accounts suggest the presence of a more federated system of governance. For example, Arrian mentions that the land beyond the Beas River was governed by "the aristocracy, who exercised their authority with justice and moderation." The Greek accounts mention the Gangaridai and the Prasii separately, although suggesting that these two were ruled by a common sovereign. Historian H. C. Raychaudhuri theorises that the Nandas held centralised control over their core territories in present-day Bihar and Uttar Pradesh, but allowed considerable autonomy in the frontier parts of their empire. This is suggested by Buddhist legends, which state Chandragupta was unable to defeat the Nandas when he attacked their capital but was successful against them when he gradually conquered the frontier regions of their empire. The Nanda kings appear to have strengthened the Magadha kingdom ruled by their Haryanka and Shaishunaga predecessors, creating the first great empire of northern India in the process. Historians have put forward various theories to explain the political success of these dynasties of Magadha. Pataliputra, the capital of Magadha, was naturally protected because of its location at the junction of the Ganges and the Son rivers. The Ganges and its tributaries connected the kingdom with important trade routes. It had fertile soil and access to lumber and elephants of the adjacent areas. Some historians have suggested that Magadha was relatively free from the Brahmanical orthodoxy, which may have played a role in its political success; however, it is difficult to assess the veracity of this claim. D. D. Kosambi theorised that Magadha's monopoly over iron ore mines played a major role in its imperial expansion, but historian Upinder Singh has disputed this theory, pointing out that Magadha did not have a monopoly over these mines, and the iron mining in the historical Magadha region started much later. Singh, however, notes that the adjoining Chota Nagpur Plateau was rich in many minerals and other raw materials, and access