Jadwiga of Anjou was the third daughter of King Louis the Great of Hungary and his wife Elisabeth of Bosnia. After the death of Casimir the Great in 1370, who left no heir in the direct male line, the throne of Poland passed to her father, who was Casimir's nephew and grandson to Vladislaus the Ell-High by his daughter Elizabeth, wife of Charles Robert of Hungary. Louis intended to leave Poland to Maria, Jadwiga's elder sister, but after his death in 1382 things took another turn. The Polish nobility, clergy and the patricians of the large towns, who had signed a treaty with Louis guaranteeing that the succession would pass to one of his daughters, did not want Sigismund of Luxembourg, Maria's future husband, as king. Therefore, instead of her, in 1384 the barely ten-year-old Jadwiga became Queen of Poland. In this way the promise given to Louis the Great had been kept, but at the same time the interests of the Polish nobility were preserved.

Jadwiga became the first and only female monarch in the history of Poland. Although she is usually referred to as a 'queen' (królowa), that title was normally used for the wife of a king and did not empower its holder to rule the country. On the other hand, the monarch had full royal rights in POland, with all the duties and privileges arising from this title. The young queen ruled for two years with the help of her advisors, the Lords of Lesser Poland. She took a personal, very active part in the conclusion of a treaty of union between Poland and Lithuania signed at Krewo in 1385, on the grounds of which Poland and Lithuania entered a personal union through the marriage of the monarch of Poland, Jadwiga, and the Grand Duke of Lithuania, Jagie³³o. The condition before the marriage could be celebrated was that the Grand Duke had to be baptised, and his lands converted to Christianity and joined to the Kingdom of Poland through a personal union. Jagie³³o, who received the baptismal name of Vladislaus, also pledged to endeavour to regain for Poland the lost province of Pomerania.

The marriage took place in 1386, and from that time the royal consorts ruled the joint state, known as the Kingdom of Poland and Grand Duchy of Lithuania. Even after the marriage, Jadwiga took an active part in political affairs: she reconciled Jagie³³o with his rebellious cousin Witold, corresponded with the Teutonic Order, which had occupied Pomerania, and led an expedition against the Ruthenian Duchy of Halicz. Soon after the celebrations Jadwiga and Jagie³³o persoannly attended to the mission sent out to their Lithuanian dominions, which were converted to Christianity. Jadwiga also kept her own court, independent of her husband's, in which, as an extremely well-educated and profoundly devout individual, she had a company of secular and ecclesiastical scholars. With the help of Jagie³³o, she restored the failing University of Cracow and obtained permission from the Pope for the foundation of a fourth, very much needed faculty, Theology, leaving the University her entire private estate as a legacy in her will. She became famous as a founder of numerous churches, altars and chauntries, monasteries and hospitals. She was the owner of the Florian Psalter, a late mediaeval illuminated multi-lingual prayer-book written specially for her, one of the earliest extant monuments of Polish writings.

Jadwiga died in 1399 of post-puerperal fever. Though she was only twenty-five, she had already built up a reputation as an exemplary monarch and died in odore sanctitatis. She was beatified in 1986 and canonised by Pope John Paul II in 1997, but was already revered by her contemporaries. According to a legend, just before her death, Jesus spoke to her from the famous Black Crucifix over a side altar she had founded at Wawel Cathedral.

Facts Queen Jadwiga was twenty-three years younger than her husband Jagie³³o. She had been advised that the Grand Duke, whom she didn't know at the time, was a barbarian and had a barbarian's conduct and looks. Before the marriage she sent her faithful knight, Zawisza of Ole¶nica, to Lithuania to verify the story. Jagie³³o received Zawisza in full confidence and took him everywhere, even to his bath-house, so that the knight could learn the truth. Upon hearing Zawisza's detailed report, Jadwiga finally agreed to the marriage.