" Unlike Alexander’s Greeks, Muslim invaders were well aware of India’s immensity, and mightily excited by its resources. As well as exotic produce like spices, peacocks, pearls, diamonds, ivory and ebony, the ‘Hindu country’ was renowned for its skilled manufactures and its bustling commerce. India’s economy was probably one of the most sophisticated in the world. Guilds regulated production and provided credit; the roads were safe, ports and markets carefully supervised, and tariffs low. Moreover capital was both plentiful and conspicuous. Since at least Roman times the subcontinent seems to have enjoyed a favourable balance of payments. Gold and silver had been accumulating long before the ‘golden Guptas’, and they continued to do so. Figures in the Mamallapuram sculptures and the Ajanta frescoes are as strung about with jewellery as those in the Sanchi and Amaravati reliefs. Divine images of solid gold are well attested and royal temples were rapidly becoming royal treasuries as successful dynasts endowed them with the fruits of their conquests. The devout Muslim, although ostensibly bent on converting the infidel, would find his zeal handsomely rewarded. "
― John Keay , India: A History