In the aftermath of World War II, European integration required not only new political institutions but also symbols capable of expressing a shared European identity. The search for a European flag formed part of this broader process. This article examines Salvador de Madariaga’s 1951 proposal for a European flag in the post-war effort to give political and cultural meaning to European unity. It connects the proposal with earlier federalist initiatives and the Congress of Europe at The Hague in 1948. As chair of the Congress’s Cultural Committee, Madariaga argued that European unity needed not only institutions but also a shared conscience through which Europeans could recognise the cultural heritage of other European nations as their own. The main source is a printed card dated December 1, 1951, preserved among the papers of the Catalan jurist and Republican exile Josep Xirau in the Arxiu Familiar Xirau-Rahola. Combining archival reconstruction, intellectual history, and analysis of symbols, the study relates it to The Hague, the European Centre of Culture, UNESCO, exile networks and the Council of Europe’s search for an emblem. It also situates the document within scholarship on European identity and Spanish Republican exile. Council of Europe records further show that Madariaga’s constellation remained under consideration until 1955 and was one of the two designs retained in the final phase of the selection process. The article argues that the flag translated Madariaga’s European conscience into visual form. Golden stars marked the capitals of the sovereign states of 1938, with a larger star for Strasbourg, while the blue field and omission of borders placed national plurality within a common European space. Its dependence on a fixed political map limited its value as a permanent emblem. The contrast with the 12-star flag adopted in 1955 shows the passage from a representation based on place and date to an abstract symbol independent of them.