Hinduism has a span of three thousand years of history in which various forms of religious experience took shape and grew into a wide and rich variety of myths and cults, beliefs and practise, doctrines and disciplines, which have nurtured millions of Hindus throughout the ages. The exact ides of Hinduism is hard to define since the beliefs and practices of the Hindus differ greatly from one period of history to another, and within a given period, from one region to another, and within a given region, from one class of society to another. In its traditional form the chief distinguishing features of its development are Vedism, Brahmanism, classical Hinduism, Sectarian Hinduism, Medieval Hinduism, Modern Hinduism and Contemporary Hinduism. These developments should not be considered as water-tight compartments, for they merge into one another. Hinduism has shown in its long history a marked propensity to assimilate rather than exclude various religious currents which once used to be considered alien to its own orthodoxy; this feature divides sharply Hinduism from other religions, for example, from Islam and to a certain extent at least in its beginning, Judaism; These religions in their strict form reject as false all other religious beliefs and practices.