The Republic of Poland is a country located in Central Europe, between Germany to the west, the Czech Republic and Slovakia to the south, Ukraine and Belarus to the east, and the Baltic Sea, Lithuania, and Russia (in the form of the Kaliningrad Oblast exclave) to the north.
Poland's first historically documented ruler, Mieszko I, was baptized in 966, adopting Catholic Christianity as the country's new official religion, to which the bulk of the population converted in the course of the next century.
The principal ports and harbours are: Port of GdaĆsk, Port of Gdynia, Port of Szczecin, Port of Swinoujscie, Port of Ustka, Port of Kolobrzeg, Gliwice, Warsaw, Wroclaw.
Poland's nobility (in Polish Szlachta) started to identify themselves with the country during the Fragmentation (Rozbicie dzielnicowe) period (1138-1320) when Poland was divided into a number of principalities under the terms of Boleslaus III's bequest to his sons.
On numerous occasions Poland's existence as a country was endangered, first, when the Polanian dukes tried to conquer lands in the 10th-13th centuries from Bohemia (Czechs), from Pomeranian, Prussian and Germans, and later, in the 17th century and afterwards, by Swedes, Russians, Prussians and Austrians.
Poland is now a member of NATO and an associate member of the European Union, of which it seeks full membership.