This article examines the idea of religious freedom as the constitutional rights of some countries. In the beginning, the principles of freedom of religion (liberty of religion) was deeply rooted and strongly associated with the concept of 'freedom of thought and conscience', a phrase that first appeared in the Westphalia Treaty of 1648 which ended a long war in the name of religion in Europe. In this context, religious freedom was understood as freedom to believe (or not believe), adhere (or not adhere) to a religious proposition, belief or doctrine on the basis of individual experience or reasoning. It also contained the freedom to change that belief at any time if desired for the reason that basically human being through out his/her life...