In 1264, the Statute of Kalisz or the General Charter of Jewish Liberties introduced numerous right for the Jews in Poland, leading to a nearly autonomous "nation within a nation".
Following the Partitions of Poland at the end of the 18th century, Poland regained its independence in 1918 with the Treaty of Versailles.
In September 1939, World War II started with the invasion of Poland by Nazi Germany, followed by the Soviet Union invading Poland in accordance with the Molotov–Ribbentrop Pact. In the aftermath of the Revolutions of 1989, most notably through the emergence of the Solidarity movement, Poland reestablished itself as a democratic republic.
Casimir III realized that the nation needed a class of educated people, especially lawyers, who could codify the country's laws and administer the courts and offices.
His efforts to create an institution of higher learning in Poland were finally rewarded when Pope Urban V granted him permission to open the University of Kraków.
In 1320, after a number of earlier unsuccessful attempts by regional rulers at uniting the Polish dukedoms, Władysław I consolidated his power, took the throne and became the first king of a reunified Poland.
His son, Casimir III (reigned 1333–70), has a reputation as one of the greatest Polish kings, and gained wide recognition for improving the country's infrastructure.
Casimir III the Great is the only Polish king to receive the title of Great.
He built extensively during his reign, and reformed the Polish army along with the country's civil and criminal laws, 1333–70.
The most famous archaeological find from the prehistory and protohistory of Poland is the Biskupin fortified settlement (now reconstructed as an open-air museum), dating from the Lusatian culture of the early Iron Age, around 700 BC.
The Slavic groups who would form Poland migrated to these areas in the second half of the 5th century AD.
Historians have postulated that throughout Late Antiquity, many distinct ethnic groups populated the regions of what is now Poland.