Intermarium
The proposed multinational polity would have incorporated territories lying between the Baltic, Black, and Adriatic Seas, hence the name Intermarium (Latin for "Between-Seas").
A Polish–Lithuanian union and military alliance had come about as a mutual response to common threats posed by the Teutonic Order, the Golden Horde, and the Grand Duchy of Moscow.
Between the November and January Uprisings, in the period between 1832 and 1861, the idea of resurrecting an updated Polish–Lithuanian Commonwealth was advocated by Prince Adam Jerzy Czartoryski, residing in exile at the Hôtel Lambert in Paris.
Subsequently, in 1795, he and his younger brother had been commanded to enter the Imperial Russian Army, and Catherine the Great had been so favourably impressed with them that she had restored to them part of their confiscated estates.
Adam Czartoryski subsequently served the Russian emperors Paul and Alexander I as a diplomat and foreign minister, establishing an anti-French coalition during the Napoleonic Wars.
[23] In his book, Essai sur la diplomatie (Essay on Diplomacy), completed in 1827 but published only in 1830, Czartoryski observed that, "Having extended her sway south and west, and being by the nature of things unreachable from the east and north, Russia becomes a source of constant threat to Europe."
[25] Czartoryski aspired above all to reconstitute—with French, British, and Ottoman support—a sort of "pan-Slavic" Polish–Lithuanian Commonwealth federated with the Czechs, Slovaks, Hungarians, Romanians, and all the South Slavs of the future Yugoslavia.
[28] Marian Kamil Dziewanowski writes that "the Prince's endeavour constitutes a [vital] link [between] the 16th-century Jagiellon [federative prototype] and Józef Piłsudski's federative-Prometheist program [that was to follow after World War I].
"[26] Józef Piłsudski's strategic goal was to resurrect an updated, democratic form of the Polish–Lithuanian Commonwealth, while working for the disintegration of the Russian Empire, and later the Soviet Union, into its ethnic constituents.
[48] In the aftermath of the Polish–Soviet War (1919–1921), and the establishment of the Ukrainian SSR, Piłsudski's concept of a federation of Central and Eastern European countries, based on a Polish-Ukrainian axis, lost any chance of realisation.
[52] According to some historians, it was the failure to create a strong counterweight to Germany and the Soviet Union, as proposed by Piłsudski, that doomed Intermarium's prospective member countries to their fates in World War II.
[30][31][53][54] The concept of a "Central [and Eastern] European Union"—a triangular geopolitical entity anchored in the Baltic, Black, and Adriatic or Aegean Seas—was revived during World War II in Władysław Sikorski's Polish Government-in-Exile.
A first step toward its implementation—1942 discussions among the Greek, Yugoslav, Polish, and Czechoslovak governments-in- exile regarding prospective Greek–Yugoslav and Polish–Czechoslovak federations—ultimately foundered on Soviet opposition, which led to Czech hesitation and Allied indifference or hostility.
[57] On 6 August 2015, Polish President Andrzej Duda, in his inaugural address, announced plans to build a regional alliance of Central European states, modeled on the Intermarium concept.
