The consolidation policy initiated by Władysław I. was by his son Kazimierz III. Wielki (Casimir the Great, 1333–70), successfully continued, with the development of the country (German eastern settlement) and the establishment of a functioning administration was the main concern. His generous policy towards the Jews encouraged their immigration. In the simmering conflict with Bohemia over Silesia and with the religious order around Pomerania (Peace of Kalisch [Kalisz], 1343) he relented in order to bring the Mazovian principalities into feudal dependency, to conquer the province of Redussia with Hungarian support in 1349/52 and to expand of his empire, which has grown to 240,000 km2, to the southeast. Since he had remained in four marriages without a male heir, he met an hereditary brotherhood with the Anjou ruling house in Hungary, which was to secure the successor to his nephew Ludwik (Ludwig). Since Ludwik I. Wielki (Ludwig I., the great, 1370–82), had no sons, the consent of the Polish nobility (Schlachta [Szlachta]) to succeed the daughters had to be bought with far-reaching concessions (privileges from Buda 1355 and Kaschau 1373/74), which required extensive tax exemption, the political The right to sole representation and participation in the election of a king included. The crown and state officials as well as most of the bishops were allowed to be appointed from the nobility, which merged into a homogeneous stratum in the course of the 15th century.
Through the marriage (1386) of Ludwik’s daughter, Hedwig (Jadwiga), with the Grand Duke of Lithuania, Jagiełło (Jogaila), a – several times interrupted (1440–47, 1492–1501) – Polish-Lithuanian personal union was established, which was not established until 1569 was converted into a real union in Lublin. Jagiełło, as King of Poland Władysław II (1386–1434), who converted to Latin Christianity with the pagan majority of his people, initiated – at times in rivalry with his cousin Witold (Vytautas) - an east and south-east oriented policy, which already in 1387 led to the feudal dependence of the Principality of Moldova.
In the conflict with the Teutonic Order, the victory of Tannenberg in 1410 (also known as the Battle of Grunwald) in the 1st Peace of Thorner (1411) was not used. a. 1454–66 came to further wars. In the 2nd Peace of Thornton (1466) the order had to renounce Pomeranian with Danzig, the Culmer and Michelauer Land, Elbing and the Marienburg; Eastern Prussia with Königsberg remained for the knights as a Polish fief. After renewed fighting at the beginning of the 16th century, Grand Master Albrecht took over von Brandenburg-Ansbach in 1525 the secularized “Prussian ducal share” recorded by the Reformation as a fiefdom. According to ehealthfacts, the duchy of Prussia fell to Brandenburg in 1618 when the electoral-Brandenburg line was also enfeoffed in 1568 and had to be given up completely by Poland in the Treaty of Wehlau in 1657.
To secure the crown of Bohemia in 1420, the initiatives launched, the Jagiellonian house, could only under Kazimierz IV. Jagielończyk (Casimir IV. Andreas, the Jagiellonian, 1447-92) to be substantiated his eldest son, Władysław (Ladislaus), 1469/71 of was appointed to the Bohemian Estates. In 1490 he also gained control of Hungary, which his uncle Władysław III. (1434–44) had held since 1440. Between 1490 and 1526, the Jagiellonians controlled the east-central European belt of states stretching from the Baltic Sea and Bohemian Forest to the Black Sea, but were exposed to the threat of the Grand Duchy of Moscow and the Ottomans. The legacy of Ludwig II. of Bohemia and Hungary came to the Habsburgs in 1526.
The battles against the Crimean Tatars supported by the Turks, which lasted with a few interruptions from 1478 to 1533, led to the loss of the Black Sea coast and the release of the Moldavia from Polish vassalage. The by the Moscow Grand DukeIvan III. operated “Collection of the Russian Land”, favored by the conversion of Lithuanian Orthodox subjects, also continued his successor Vasily III. consistently continue; in the five wars between 1486 and 1533 Lithuania suffered a. Severia and Smolensk a.
The frequent foreign policy entanglements were used by the Polish-Lithuanian nobility, which was growing together into a single unit, to wrest more extensive rights from their rulers. According to a Habeas Corpus Act (1430/33), the regional petty nobility was granted participation in the state government in 1454, which in 1493 led to the establishment of a two-chamber system (senate and messenger room). After 1505, the king had to convene the Reichstag, formed by elected country messengers, every two years and carry out its resolutions. The monopoly of aristocratic landed property, which was tightened in 1538, and the privileged social and political position of the nobility paved the way for the decline of the cities and the disenfranchisement and exploitation of the peasants.