Despite lacking an overseas empire , Poland maintained a slow but steady level of economic development. The cultural hubs of interwar Poland – Warsaw , Kraków , Poznań , Wilno and Lwów – became major European cities and the sites of internationally acclaimed universities and other institutions of higher education. By 1939, the Republic had become "one of Europe's major powers". [ 1 ] Nevertheless, the Polish economist Witold Gadomski has calculated that the Republic was a much poorer nation than contemporary Poland. According to his estimates, Poland's gross national product in 1929 was between 50 and 60 billion US$s, which compares starkly with an estimate in 2007 of 422 billion dollars. In 2007, Poland's share in international trade was 1.1%, while in 1937, it was 0.8%. [ 2 ] On 5 November, in Lublin , the first Soviet of Delegates was created. On 6 November the Communists announced the creation of a Republic of Tarnobrzeg . The same day, a Provisional People's Government of the Republic of Poland was created in Lublin under the Socialist, Ignacy Daszyński . On Sunday, 10 November at 7 a.m., Józef Piłsudski , newly freed from 16-month imprisonment by the German authorities at Magdeburg , returned by train to Warsaw. Piłsudski, together with Colonel Kazimierz Sosnkowski , was greeted at Warsaw's rail station by Regent Zdzisław Lubomirski and Colonel Adam Koc . Next day, due to his popularity and support from most political parties, the Regency Council appointed Piłsudski Commander in Chief of the