Smaller states would send and receive envoys, who were a rung below ambassador. Somewhere between the two was the position of minister plenipotentiary. Diplomacy was a complex affair, even more so than now. The ambassadors from each state were ranked by complex levels of precedence that were much disputed. States were normally ranked by the title of the sovereign; for Catholic nations the emissary from the Vatican was paramount, then those from the kingdoms, then those from duchies and principalities. Representatives from republics were ranked the lowest (which often angered the leaders of the numerous German, Scandinavian and Italian republics). Determining precedence between two kingdoms depended on a number of factors that often fluctuated, leading to near-constant squabbling. Ambassadors were often nobles with little foreign experience and no expectation of a career in diplomacy. They were supported by their embassy staff. These professionals would be sent on longer assignments and would be far more knowledgeable than the higher-ranking officials about the host country. Embassy staff would include a wide range of employees, including some dedicated to espionage. The need for skilled individuals to staff embassies was met by the graduates of universities, and this led to a great increase in the study of international law, French, and history at universities throughout Europe. At the same time, permanent foreign ministries began to be established in almost all European states to coordinate embassies and their staffs. These ministries were still far from their modern form, and many of them had extraneous internal responsibilities. Britain had two departments with frequently overlapping powers until 1782. They were also far smaller than they are currently. France, which boasted the largest foreign affairs department, had only some 70 full-time employees in the 1780s. The elements of modern diplomacy slowly spread to Eastern Europe and Russia, arriving by the early 18th century. The entire edifice would be greatly disrupted by the French Revolution and the subsequent years of warfare. The revolution would see commoners take over the diplomacy of the French state, and of those conquered by revolutionary armies. Ranks of precedence were abolished. Napoleon also refused to acknowledge diplomatic immunity, imprisoning several British diplomats accused of scheming against France. After the fall of Napoleon, the Congress of Vienna of 1815 established an international system of diplomatic rank. Disputes on precedence among nations (and therefore the appropriate diplomatic ranks used) were first addressed at the Congress of