The first recognizable historical narrative of India, the Rajataringini (River of Kings ), composed in the middle of the twelfth century by a Kashmiri Brahman, Kalhana, speaks of the mythic origins of the valley in a sacred lake. Marine fossils found by modern researchers lend credence to the legends. According to the Rajataringini, early caste-based Hindu society was overlain by Buddhist elements but never completely displaced. Hindu dynasties continued to rule until the early fourteenth century when Islam was brought to Kashmir by kings and Sufi Missionaries from central Asia, Afghanistan, and Persia. Tradition has it that only a handful of families of Brahmans survived the twin processes of conversion and elimination. These were the ancestors of the Pandits of today. Kashmir was incorporated into the Mughal Empire in the late sixteenth century. The liberal religious policy of the Mughals led to a gradual reassertion of the place of Kashmiri Brahmans in their native land. Many, however, migrated out of Kashmir. It was in response to the request from some of these Brahmans that the use of the appellation "Pandit" as an honorific title was approved by the Mughal emperor in the eighteenth century. There are today localized communities of Kashmiri Pandits in many Indian cities. According to estimates, there is one Kashmiri Pandit outside Kashmir for every three living there. The Nehru family were Pandits.