Prospectively a federation[1][2][3][4][5] of Central and Eastern European countries, the post-World War I Intermarium plan pursued by Polish leader and former political prisoner of the Russian Empire, Józef Piłsudski (1867–1935), sought to recruit to the proposed federation the Baltic states (Lithuania, Latvia, Estonia), Finland,[6] Belarus, Ukraine, Hungary, Romania, Yugoslavia and Czechoslovakia.[7][8] The Polish name Międzymorze (from między, "between"; and morze, "sea"), meaning "Between-Seas", was rendered into Latin as "Intermarium."[9]