"Finally, however, under the onslaught of Islam, from the eighth century to the tenth, both Buddhist and Manichaean as well as the Nestorian Christian culture and monuments of the region were destroyed.... In the north very little survives of the ancient edifices that were there prior to the Muslim conquest: only a few mutilated religious sites remain. It is clear from Indian literature that both temples and images must have existed in the second century BC and perhaps earlier. Very little architectural evidence remains, however, antedating the epoch of the Gupta dynasty (C. AD 320-650), for it was precisely in the Ganges Valley, the central and chief area of the Gupta empire, that the Muslim empire flourished a millennium later and most of the monuments above ground were destroyed by the sectarian zeal of Islam. The oldest stone ruins that have been found represent not the beginnings of a style, but fully developed forms... Since the earliest important body of Indian art surviving to us stems from the century of Asoka, it is predominantly Buddhist. During subsequent periods, however, Buddhist and Hindu (Brahmanical) themes alternate in rich profusion. The two traditions flourished side by side, even sharing colleges and monasteries, for nearly two millenniums, until about the height of the Muslim conquest (C. AD 1200), Buddhism disappeared from the land of its birth."