the Diet: but during his reign Poland was treated merely as an appanage of Hungary. After the death of Louis of Hungary without male issue (1382) Hedwig, daughter of Casimir the Great, was chosen Queen of Poland in 1384 by the Diet, and two years later she married Jagello (Jagellon), Grand Prince of Lithuania, who ascended the throne as Ladislas II. (q.v.), and founded the Jagellon dynasty, which ruled over Poland and Lithuania from 1386 to 1572, and under which Poland was at the height of its greatness. Jagello, at his accession, embraced Christianity, which was now introduced into Lithuania, hitherto a heathen country. Jagello inflicted a great defeat upon the Teutonic Knights at Tannenberg in 1410. He was succeeded in Poland by his elder son, Ladislas III. (1434-44), and in Lithuania by his younger son, Casimir. Ladislas, whom the Hungarians placed upon their throne, was overwhelmed by the Turks and slain in the battle of Varna. He was succeeded after an interregnum by his brother, Casimir IV. (1447-92), during whose reign the Teutonic Knights, by the Treaty of Thorn (1466), ceded West Prussia to Poland, and agreed to hold East Prussia as a Polish fief. Casimir rewarded the inferior nobles, or warrior class, with more extensive privileges, putting them on an equality of rank with the great chiefs of the realm, and at the same time necessarily oppressing the peasantry. Manufactures and commerce revived to a remarkable extent in the western provinces. The brief reigns of his two elder sons, John I. (1492-1501) and Alexander (1501-06), were marked only by the increased power of the Diet, which was steadily absorbing the real authority, and converting Poland from a monarchy to an oligarchy.
Sigismund I., surnamed the Great (1506-48), the youngest son of Casimir IV., raised the country to the utmost pitch of prosperity. Generous and enlightened, he was beloved by the masses, while his firmness and justice commanded the respect of the turbulent nobles. In a war with Russia, however, in the early part of his reign, he lost Smolensk. His son Sigismund II., Augustus (1548-72), was a worthy successor to his father. During his reign the extraordinary privileges of the higher nobles were curtailed or abolished. Lithuania was finally joined indissolubly to Poland, the union being proclaimed by a Diet held at Lublin in 1549. There was but one Diet for the united realm, which was to be converted into an elective monarchy on the death of the reigning King, who had no heirs. Lithuania retained, however, her own army, treasury, and laws. Lithuania was at the same time reduced in area by the annexation of Podlachia, Volhynia, and the Ukraine to Poland. Livonia was ceded to Poland by the Knights Sword-bearers and successful wars were waged against the Russians and the Turks. The Polish realm then stretched across Central Europe from the Baltic Sea to the Dniester, with its western boundary less than 90 miles from Berlin, and its eastern frontier about 150 miles from Moscow, covering an area of more than 370,000 square miles. The population almost doubled under the two Sigismunds. The Reformation spread rapidly in Poland, but its progress was arrested by the Jesuits, who persuaded the nobles that their interests lay in the preservation of the Catholic hierarchy. With the death of Sigismund Augustus in 1572 the Jagellon dynasty became extinct and Poland passed under the regime of elected kings. The election was by the two chambers of the Diet, the Senate or Chamber of the Chief Nobles, and the Chamber of Nuncios, or Representatives of the Inferior Nobles. The Diet sat only six weeks, and its decisions were required to be unanimous; so that if the liberum veto (the right of forbidding the passing of any measure) were freely exercised even by a single member, all legislation was at a standstill. More unnatural still was the recognized right of any number of nobles to confederate for the purpose of effecting their will by force of arms.
This singular constitution produced the most inefficient government that was ever established in a great State. Political factions could hamper all action in great national crises, and the so-called republic became a most pernicious oligarchy. In the liberum veto might easily be found the seed which produced the final disintegration. The first elective monarch was Henry of Valois, Duke of Anjou (1573-74), who had barely assumed the crown when he laid it down to become King of France as Henry III., and was succeeded by Stephen Báthory (1575-86), Voivode of Transylvania. Stephen's successor, Sigismund III., Vasa (1587-1632), was the son of John III. of Sweden by a daughter of Sigismund I. His claims to the crown of Sweden, which he wore for a time, brought on wars with that kingdom. Gustavus Adolphus carried on victorious campaigns against the Poles in 1621-29 and conquered Livonia. After Sigismund III., under whom Warsaw supplanted Cracow as the Polish capital, came his two sons, Ladislas IV. (1632-48) and John Casimir (1648-68). The imprudent attempts of the sovereigns of the House of Vasa to amend the Constitution only excited the suspicion of the nobles, and led to a further curtailment of royal authority. In 1648 the Cossacks, goaded by oppression, rose in rebellion under Bogdan Chmielnicki (q.v.), put themselves under the protection of Russia (1654), and ever afterwards proved themselves the most inveterate enemies of the Poles. In 1655 Charles X. of Sweden invaded Poland while the Poles were engaged in war with Russia, and in 1656 he was joined by Frederick William, the Great Elector of Brandenburg. The Poles at first fought victoriously under Czarneeki, but in July, 1650, they were vanquished in a great battle at Warsaw. In 1657 Brandenburg went over to the side of Poland, which then renounced its suzerainty over the Duchy of Prussia (East Prussia). In the Peace of Oliva, in 1660, Poland formally ceded Livonia to Russia, and the Ukraine beyond the Dnieper was given up to Russia in the Treaty of Andrussovo, in 1667. Michael Wisniowiecki (1669-73), the son of one of the ablest Polish leaders, but himself an imbecile, was elected as successor to John Casimir, who had abdicated the throne. A war with Turkey, concluded, in spite of the victories of John Sobieski, by an ignominious peace, was the chief event of his reign. In 1674 the crown was conferred on John Sobieski, who shed lustre on the Polish arms by overthrowing, in conjunction with the German princes, a vast Turkish army in front of Vienna in 1683, and saving the Hapsburg capital. His reign, however, was productive of little good to the internal administration. He died in 1696 and the French Prince de Conti was elected and proclaimed King. Lack-
