Pre-Napoleon
In 1693, William Penn looked at 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 in to the political reality of Europe at the time.
In 1728, Abbot Charles de Saint-Pierre proposed the creation of a European league of 18 sovereign states, with common treasury, no borders and an economic union.
After the American War of Independence 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 and Tadeusz Kościuszko.
Some suggestion of a European union can be inferred from Immanuel Kant's 1795 proposal for an "eternal peace congress".
Read more about this topic: Ideas Of European Unity Before 1945