Alternate theories for the spread of sati include it expanding from Kshatriya caste to others castes, not because of wars, but on its own, as part of "Sanskritization" and a cultural phenomenon that conflated sati as a caste status symbol. This theory has been challenged because it does not explain the spread of sati from Kashatriyas to Brahmins, and Brahmins were not considered to be of inferior caste status than Kshatriyas. Roshen Dalal postulated that its mention in some of the Puranas indicates that it slowly grew in prevalence from 5th-7th century and later became an accepted custom around 1000 AD among those of higher classes, especially the Rajputs.