sary, allowing Poland's and Lithuania's territorial expansion into the far north region of Livonia. In 1466, after the Thirteen Years' War, King Casimir IV Jagiellon gave royal consent to the milestone Peace of Thorn, which created the future Duchy of Prussia, a Polish vassal. The Jagiellons at one point also established dynastic control over the kingdoms of Bohemia (1471 onwards) and Hungary. In the south Poland confronted the Ottoman Empire and the Crimean Tatars (by whom they were attacked on 75 separate occasions between 1474 and 1569), and in the east helped Lithuania fight the Grand Duchy of Moscow. Some historians estimate that Crimean Tatar slave-raiding cost Poland one million of its population from 1494 to 1694.
Poland was developing as a feudal state, with a predominantly agricultural economy and an increasingly powerful landed nobility. The Nihil novi act adopted by the Polish Sejm (parliament) in 1505, transferred most of the legislative power from the monarch to the Sejm, an event which marked the beginning of the period known as "Golden Liberty", when the state was ruled by the "free and equal" Polish nobility. Protestant Reformation movements made deep inroads into Polish Christianity, which resulted in the establishment of policies promoting religious tolerance, unique in Europe at that time. It is believed that this tolerance allowed the country to avoid the religious turmoil that spread over Europe during the late Middle Ages. The European Renaissance evoked in late Jagiellon Poland (kings Sigismund I the Old and Sigismund II Augustus) a sense of urgency in the need to promote a cultural awakening, and resultantly during this period Polish culture and the nation's economy flourished. In 1543 the Pole, Nicolaus Copernicus, an astronomer from ToruĊ, published his epochal works, De revolutionibus orbium coelestium (On the Revolutions of the Celestial Spheres), and thus became the first proponent of a predictive mathematical model confirming
