 Jackson states that, contrary to the theoretical model of caste where Kshatriyas only could be warriors and soldiers, historical evidence confirms that Hindu warriors and soldiers during the medieval era included other castes such as Vaishyas and Shudras.Further, there is no evidence, writes Jackson, that there ever was a "widespread conversion to Islam at the turn of twelfth century" by Hindus of lower caste.Jamal Malik, a professor of Islamic studies, extends this observation further, and states that "at no time in history did Hindus of low caste convert "en masse" to Islam".