International relations, 1648–1814 and cultural achievement. Historian Frederick Nussbaum says it was: The worst came during the Thirty Years' War, 1618–1648, which had an extremely negative impact on the civilian population of Germany and surrounding areas, with massive loss of life and disruption of the economy and society. Scholars taking a "realist" perspective on wars and diplomacy have emphasized the Peace of Westphalia (1648) as a dividing line. It ended the Thirty Years War (1618–1648), where religion and ideology had been powerful motivating forces for warfare. Westphalia, in the realist view, ushered in a new international system of sovereign states of roughly equal
Conventional warfare by Plato, then found more acceptance in the consolidation of power under the Roman Catholic Church. European monarchs then gained power as the Catholic Church was stripped of temporal power and was replaced by the divine right of kings. In 1648, the powers of Europe signed the Treaty of Westphalia which ended the religious violence for purely political governance and outlook, signifying the birth of the modern 'state'. Within this statist paradigm, only the state and its appointed representatives were allowed to bear arms and enter into war. In fact, war was only understood as a conflict between sovereign states.