Diplomatic history deals with the history of international relations between states. Diplomatic history can be different from international relations in that the former can concern itself with the foreign policy of one state while the latter deals with relations between two or more states. Diplomatic history tends to be more concerned with the history of diplomacy, but international relations concern more with current events and creating a model intended to shed explanatory light on international politics. Diplomacy#History In the 5th century BCE Thucydides was highly concerned with the relations among states. However Leopold von Ranke (1795-1886), the leading German historian of the 19th century CE, codified the modern form of diplomatic history. Ranke wrote largely on the history of Early Modern Europe, using the diplomatic archives of the European powers (particularly the Venetians) to construct a detailed understanding of the history of Europe wie es eigentlich gewesen ist ("as it actually happened"). Ranke saw diplomatic history as the most important kind of history to write because of his idea of the "Primacy of Foreign Affairs" (Primat der Aussenpolitik), arguing that the concerns of international relations drive the internal development of the state. Ranke's understanding of diplomatic history relied on using as sources the large number of official documents produced by modern western governments; he argued that historians should examine such sources in an objective and neutral spirit. In the early 20th centuries, work by prominent diplomatic historians such as Charles Webster, Harold Temperley, Alfred Pribram, R.H. Lord and B.E. Schmitt were mostly concerned with the events such as the Napoleonic Wars, the Congress of Vienna and the origins of the Franco-German War. A notable event in diplomatic history occurred in 1910 when the French government start to publish all of the archives relating to the war of 1870. The Bolsheviks in Russia published key secret papers from the Allies in 1918.