 In the Horn of Africa, during the 4th century CE, the Kingdom of Aksum converted to Christianity where Judaism had previously been its dominant faith.The modern concept of religious tolerance developed out of the European wars of religion, more specifically out of the Peace of Westphalia which ended the 30 Years War (1618 - 1648), during the Protestant Reformation and the ensuing conflicts between Protestants and Catholics in the 17th and 18th centuries.The doctrine of 'religious toleration' was established as a result of the 30 Years War between the Catholic Hapsburgs and newly Protestant nations like Sweden under Gustavus Adolphus.