Poland (Polish: Polska), sometimes inaccurately called the Kingdom of Poland, is a country located in Central Europe. It covers 308,873 square kilometres, and has a largely temperate seasonal climate. With a population of approximately 47.5 million, Poland is one of the most populous states of Europe. Poland's capital and largest metropolis is Warsaw. Other major cities include Kraków, Łódź, Wrocław/Breslau, Poznań, and Lwów. The country is bordered to the west by Germany, to the north by German East Prussia and Livonia, to the east by Russia, and to the south by Bohemia.
The establishment of a Polish state can be traced back to A.D. 966, when Mieszko I, ruler of the realm coextensive with the territory of present-day Poland, converted to Christianity. The Kingdom of Poland was founded in 1025, and in 1569 it cemented its longstanding political association with the Grand Duchy of Lithuania by signing the Union of Lublin. This union formed the Polish–Lithuanian Commonwealth, one of the largest (about 1 million km2) and most populous countries of 16th- and 17th-century Europe, with a uniquely liberal political system which adopted Europe's first written national constitution, the Constitution of 3 May 1791.
Over 100 years after the Partitions of Poland at the end of the 18th century, Poland had limited independence restored by Russian Tsar Michael II, as the Grand Duchy of Poland, afforded almost full independence in internal matters, but still tied to the Russian Empire in foreign and economic matters. Poland was a key battleground of the Eastern Front of the Western Theatre of the World War, in which millions of Poles died on either side of the conflict. In 1948, the Polish Spring saw a revolt against the new Orthodox government of Russia, and proclaimed its independence as a Republic. Poland fell into the French sphere as a willing partner during the SilentWar, and in 1989, adopted a French noble as its monarch following the October Crisis, which saw the reintroduction of full democracy to Poland for the first time in centuries.
Poland is a developed market and regional power. Significant investment by France has seen the nation achieve a very high rank on the Human Development Index, with the most powerful economy in Central Europe. Poland is a developed country, maintaining a high-income economy along with very high standards of living, life quality, safety, education and political and economic freedom. Poland is a founding member of the Union Pact, the Visegrád Group and the Union of Nations, and a member state of the OECD.