Jadwiga (Latin Hedwig, Hungarian Hedvig) was born on October 3, 1373 or 1374 at Buda to King Louis I the Great of Hungary and Poland (Angevin dynasty) and Queen Elizabeth of Bosnia. She received the elite royal Catholic formation at the royal courts of Hungary and Poland.
In 1384, at the age of 10 or 11, Jadwiga was crowned Queen regnant of Poland (with the royal title 'Rex Poloniae' — 'King of Poland' — establishing her feminine royal-regnant sovereignty over Poland).
The decisive institutional-political-religious moment of Jadwiga's reign — and one of the most decisive moments in the entire Catholic history of Eastern Europe — was her marriage on February 18, 1386 to Grand Duke Jogaila (Jagiełło) of Lithuania (the Grand Duke of the last remaining pagan European people, the last pagan European ruler of the late 14th century).
The Jadwiga-Jogaila marriage was conditional on Jogaila's baptism and the Christianization of the entire Lithuanian people. Jogaila was baptized on February 15, 1386 (taking the Catholic name Władysław — after St. Ladislaus I of Hungary) and crowned King of Poland (as Władysław II Jagiełło) on March 4, 1386 alongside Jadwiga.
The Catholic Christianization of Lithuania (1386–1387) — the last major European conversion, undertaken systematically through the Polish-Lithuanian royal alliance produced by the Jadwiga marriage — institutionally ended the millennium-long process of European Christianization that had begun with the Emperor Constantine (313) and had been shaped by the conversion of the Franks (Clovis 496), the Anglo-Saxons (Augustine of Canterbury 597), the Bulgars (Boris I 864), the Slavs (Cyril and Methodius, 863), the Russians (Vladimir 988), and the late-medieval Baltic conversions.
Jadwiga personally undertook the funding of the restoration of the University of Kraków (Jagiellonian University) — donating her personal royal jewels for the 1400 endowment (the university subsequently named for her husband Jagiełło). The Jagiellonian University became the principal Catholic academic centre of Poland and the alma mater of Sts. John Cantius (John of Kęty), Bl. Simon of Lipnica, and subsequently Nicolaus Copernicus (1473–1543) and Pope St. John Paul II (1920–2005).
Jadwiga undertook systematic personal charity — personally caring for the Kraków poor at the royal hospital, establishing the Catholic educational and charitable institutions across her kingdom, and undertaking the personal virginal-marital discipline (maintaining the marital continence through the first 13 years of the Jadwiga-Jagiełło marriage until the final year).
On July 17, 1399, at the age of 25, Jadwiga died in childbirth at Wawel Royal Castle — the daughter Elisabeth Bonifacia died almost immediately after Jadwiga.
Her canonization by Pope St. John Paul II on June 8, 1997 at Kraków (during his apostolic visit to Poland) — the papal recognition of the continuing 598-year Polish Catholic devotion to Jadwiga — institutionally recognized her patronage of the Lithuanian Christianization and the Jagiellonian University tradition.