This article aims to cover ideas of European unity before the formation of the first bodies of what is now the European Union in 1948.

Early history

Ancient concepts of European unity were generally undemocratic, and founded on domination, like the Empire of Alexander the Great, the Roman Empire, or the Catholic Church controlled by the Pope in Rome. The first major phase of European unification can be traced to the Greco-Roman world.

"Europe" as a cultural sphere is first used during the Carolingian dynasty to encompass the Latin Church (as opposed to Eastern Orthodoxy). The first mention of the concepts of "Europe" and "European" dates back to 754 in the Mozarabic Chronicle. The Chronicle contains the earliest known reference in a Latin text to "Europeans" (europenses), whom it describes as having defeated the Umayyads at the Battle of Tours (732).Kwame Anthony Appiah (2012), "Misunderstanding cultures: Islam and the West", Philosophy and Social Criticism 38(4–5) 425–33.Evert Van De Poll (2013), Europe and the Gospel: Past Influences, Current Developments, Mission Challenges (Versita), p. 55.

Italian poet Dante Alighieri proposed an idea of peaceful European union in his De Monarchia (1310s). Because of this, in Italy he is often considered a "European federalist ahead of his time".

In the Renaissance, medieval trade flourished in organisations like the Hanseatic League, stretching from English towns like Boston and London, to Frankfurt, Stockholm and Riga. These traders developed the , spreading basic norms of good faith and fair dealing through their business.

Modern era

Democratic ideals of integration for international and European nations are as old as the modern nation state.

In 1517, the Protestant Reformation triggered a hundred years of crisis and instability. Martin Luther nailed a list of demands to the church door of Wittenberg, King Henry VIII declared a unilateral split from Rome with the Act of Supremacy 1534, and conflicts flared across the Holy Roman Empire until the Peace of Augsburg 1555 guaranteed each principality the right to its chosen religion (cuius regio, eius religio). This unstable settlement unravelled in the Thirty Years' War (1618–1648), killing around a quarter of the population in central Europe. The Treaty of Westphalia 1648, which brought peace according to a system of international law inspired by Hugo Grotius, is generally acknowledged as the beginning of the nation-state system. Even then, the English Civil War broke out and only ended with the Glorious Revolution of 1688, by Parliament inviting William and Mary from Hannover to the throne, and passing the Bill of Rights 1689.

In 1693, William Penn, a Quaker from London, reacted to the devastation of war in Europe and wrote of a "European dyet, or parliament", to prevent further war, without further defining how such an institution would fit into the political reality of Europe at the time.W Penn, An ESSAY towards the Present and Future Peace of Europe by the Establishment of an European Dyet, Parliament, or Estates (1693) in AR Murphy, The Political Writings of William Penn (2002) See D Urwin, The Community of Europe: A History of European Integration (1995)

In 1713, Abbot Charles de Saint-Pierre proposed the creation of a European league ("Perpetual Union") of 18 sovereign states, with a common treasury, no internal borders and an economic union. (cited in The Economist, 2127 August 2021, page 26) The project was taken up by Jean-Jacques Rousseau,JJ Rousseau, A lasting peace through the federation of Europe; and, The state of war (1756) and Immanuel Kant after him.I Kant, Perpetual Peace: A Philosophical Sketch or Zum ewigen Frieden. Ein philosophischer Entwurf (1795) Some suggestion of a European union can be inferred from Kant's 1795 proposal for an "eternal peace congress".

The Welsh intellectual Richard Price wrote about an idea for a “united states” of Europe that would maintain liberty and ensure peace on the continent in his Observations on the Nature of Civil Liberty pamphlet about how to resolve the issue with the American colonies in 1776..

After the American Revolutionary War the vision of a United States of Europe, similar to the United States of America, was shared by a few prominent Europeans, notably the Marquis de Lafayette, Henri de Saint-Simon, and Tadeusz Kościuszko.

19th century

The concept of "Europe" referring to Western Europe or Germanic Europe arose in the 19th century, contrasting with the Russian Empire, as is evidenced in Russian philosopher Danilevsky's Russia and Europe.

In the 1800s, a customs union under Napoleon Bonaparte's Continental System was promulgated in November 1806 as an embargo of British goods in the interests of the French hegemony. Felix Markham notes how during a conversation on St. Helena, Napoleon remarked, "Europe thus divided into nationalities freely formed and free internally, peace between States would have become easier: the United States of Europe would become a possibility."Felix Markham, Napoleon (New York: Penguin Books USA Inc., 1966), 257 as quoted in Matthew Zarzeczny, Napoleon's European Union: The Grand Empire of the United States of Europe (Kent State University Master's thesis), 2.

The French socialists Saint-Simon and Augustin Thierry would in 1814 write the essay De la réorganisation de la société européenne, already conjuring up some form of parliamentary European federation.

In the conservative reaction after Napoleon's defeat in 1815, the German Confederation () was established as a loose association of thirty-eight sovereign German states formed by the Congress of Vienna. Napoleon had swept away the Holy Roman Empire and simplified the map of Germany. In 1834, the Zollverein ("customs union") was formed among the states of the Confederation, to create better trade flow and reduce internal competition. In spite of the allusion by Fritz Fischer in Germany's Aims in the First World War that an extension of this customs union may have become the model for a unified Europe, the ensuing North German Confederation established in 1866 drifted away from the inclusive multinational character of the preceding German Confederation and the early Kingdom of Prussia, taking instead the direction of staunch German nationalism and brutal subjugation of other nations living within the borders of the succeeding German Empire. The then current and influential German ideas of geopolitics and a Mitteleuropa later became increasingly degenerated due to their underlying principle of German national hegemony, a process culminating in the abhorrent vision laid out by the national socialists of European unity understood as universal servitude of the European nations to the Germans (see below), thus contradicting directly the current intellectual framework for European Union.

On 3 May 1831 the Polish polymath Wojciech Jastrzębowski published On Lasting Peace among the Nations, framing a constitution for a Europe united as a single republic with no internal borders, with a unified legal system, and with institutions staffed by representatives from all of Europe's peoples.

In 1834, Giuseppe Mazzini founded Young Europe (), an international political association on the model of Young Italy. It was composed of the national societies of Young Italy, Young Poland and Young Germany, which, independent in their own spheres, acted in common, through a central committee, for the furthering of the principles of liberty, equality, and humanity in Europe. The headquarters of the society were in Switzerland, where, in 1835–36, the organization of a French society, Young France, was brought about. The activity of the society speedily aroused the opposition of the Swiss authorities, who expelled many of its members from the country.

Giuseppe Mazzini set the stage for perhaps the best known early proposal for peaceful unification, through cooperation and equality of membership, made in 1847 by the pacifist Victor Hugo. Hugo used the term United States of Europe () during a speech at the International Peace Congress organised by Mazzini, held in Paris in 1849. Hugo favoured the creation of "a supreme, sovereign senate, which will be to Europe what parliament is to England" and said: "A day will come when all nations on our continent will form a European brotherhood ... A day will come when we shall see ... the United States of America and the United States of Europe face to face, reaching out for each other across the seas." He was laughed out of the hall, but returned to his idea again in 1851. Hugo planted an oak tree in the grounds of his residence on the Island of Guernsey, saying that when this tree matured the United States of Europe would have come into being. The tree to this day grows in the gardens of Maison de Hauteville, St. Peter Port, Guernsey, Victor Hugo's residence during his exile from France.

The Italian philosopher Carlo Cattaneo wrote "The ocean is rough and whirling, and the currents go to two possible endings: the autocrat, or the United States of Europe". In 1867, Giuseppe Garibaldi, and John Stuart Mill joined Victor Hugo at the first congress of the League of Peace and Freedom in Geneva. Here the anarchist Mikhail Bakunin stated "That in order to achieve the triumph of liberty, justice and peace in the international relations of Europe, and to render civil war impossible among the various peoples which make up the European family, only a single course lies open: to constitute the United States of Europe". The French National Assembly, also called for a United States of Europe on 1 March 1871.

As part of 19th-century concerns about an ailing Europe and the threat posed by the Mahdi, the Polish writer Theodore de Korwin Szymanowski's original contribution was to focus not on nationalism, sovereignty, and federation, but foremost on economics, statistics, monetary policy, and parliamentary reform. His L'Avenir économique, politique et social en Europe (The Future of Europe in Economic, Political and Social Terms), published in Paris in 1885, was in effect a blueprint for a unified Europe with a customs union, a central statistical office, a central bank, and a single currency.

H. G. Wells' 1901 book Anticipations included his prediction that by the year 2000, following the defeat of German imperialism "on land and at sea," there would come into being a European Union.

Between the World Wars

World War I devastated Europe's society and economy, and the Versailles Treaty failed to establish a workable international system in the League of Nations, any European integration, and imposed punishing terms of reparation payments for the losing countries.See JM Keynes, The Economic Consequences of the Peace (1919)

Following the war, thinkers and visionaries from a range of political traditions again began to float the idea of a politically unified Europe. In the early 1920s a range of internationals were founded (or re-founded) to help like-minded political parties to coordinate their activities. These ranged from the Comintern (1919), to the Labour and Socialist International (1921) to the Radical and Democratic Entente of centre-left progressive parties (1924), to the Green International of farmers' parties (1923), to the centre-right International Secretariat of Democratic Parties Inspired by Christianity (1925). While the remit of these internationals was global, the predominance of political parties from Europe meant that they facilitated interaction between the adherents of a given ideology, across European borders. Within each political tradition, voices emerged advocating not merely the cooperation of various national parties, but the pursuit of political institutions at the European level.