On 11 January 1917, Ignacy Jan Paderewski, a brilliant pianist and the unofficial Polish representative in the United States, delivered a memorandum to US President Woodrow Wilson. Paderewski’s main objective was to win Wilson’s support for the independence of Poland. This chapter discusses the reasons for the popularity of Polish federalist ideas towards the end of the First World War, which were almost completely marginalised in the interwar period. The ‘free federation’ of the type Paderewski suggested stood indeed at the centre of Polish political thought during the war. Following the outbreak of the conflict, the notion became increasingly popular in East Central Europe, where the ideal of centralism had been hitherto prevalent. In the Austrian part of the Dual Monarchy, Polish political elites also hoped for a reconstruction of the political order. The smallest promises came from the empire that eventually created a semi-independent Polish state in November 1916.