[<< wikibooks] Saylor.org's Ancient Civilizations of the World/The Classical Age in India
New kingdoms rose to power in Ganges River valley by 500 B.C.E. Urbanization emerged in the capitals of these kingdoms and near major religious temples. But by the sixth century B.C.E., religious thinkers were beginning to challenge the rituals on which the Brahman elite—Vedic priests—depended. The most important of these thinkers, the Buddha, created a new religion that would have world-wide significance. Moreover, the rivalry between Buddhism and Vedic religion, later known as Hinduism, shaped the nature of Indian culture for many centuries. But out of this turmoil India entered a “Golden Age” under the rule of the Gupta dynasty. During this era, new and sophisticated ideas about literature, art, and science became fixtures of Gupta society. 
In this unit, we will see that classical India during this period was defined by political disunity and religious conflict broken only briefly by unification under the Guptas.