The Ventotene Manifesto is a political document written in 1941 by Italian political exiles, including Altiero Spinelli and Ernesto Rossi, while they were imprisoned on the island of Ventotene. The manifesto advocates for a united Europe as a means to prevent future wars and promote peace, emphasizing the importance of federalism and democracy. The document argues that nationalism leads to conflict and that a cooperative European framework is essential for stability. It has been influential in shaping the ideas behind the formation of the European Union and remains a significant reference for discussions on European integration and unity.