The Jagiellonian (US: /ˌjɑːɡjəˈloʊniən/ YAH-gyə-LOH-nee-ən) or Jagellonian dynasty (US: /ˌjɑːɡəˈ-/ YAH-gə-; Lithuanian: Jogailaičių dinastija; Polish: dynastia jagiellońska), otherwise the Jagiellon dynasty (Polish: dynastia Jagiellonów), the House of Jagiellon (Polish: Dom Jagiellonów), or simply the Jagiellons (Lithuanian: Jogailaičiai; Polish: Jagiellonowie; Latin: Iagellonidae), was the name assumed by a cadet branch of the Lithuanian ducal dynasty of Gediminids upon reception by Jogaila, the Grand Duke of Lithuania, of baptism as Ladislaus in 1386, which paved the way to his ensuing marriage to the Queen Regnant Hedwig of Poland, resulting in his ascension to the Crown of the Kingdom of Poland as Ladislaus II Jagiełło (initially ruling jure uxoris jointly with Jadwiga until her death), and the effective promotion of his branch to a royal dynasty. The Jagiellons were polyglots and per historical evidence Casimir IV Jagiellon and his son Saint Casimir possibly were the last Jagiellons who spoke in their patrilineal ancestors' Lithuanian language; however, even the last patrilineal Jagiellonian monarch Sigismund II Augustus maintained two separate and equally lavish Lithuanian-speaking and Polish-speaking royal courts in Lithuania's capital Vilnius. The Jagiellons reigned in several European countries between the 14th and 16th centuries. Members of the dynasty were Kings of Poland (1386–1572), Grand Dukes of Lithuania (1377–1392 and 1440–1572), Kings of Hungary (1440–1444 and 1490–1526), and Kings of Bohemia and imperial electors (1471–1526).
The personal union between the Kingdom of Poland and the Grand Duchy of Lithuania (converted in 1569 with the Treaty of Lublin into the Polish–Lithuanian Commonwealth) is the reason for the common appellation "Poland–Lithuania" in discussions about the area from the Late Middle Ages onward. One Jagiellon, Ladislaus III of Poland, briefly ruled both Poland and Hungary (1440–1444), and two others ruled both Bohemia and Hungary (1490–1526) and then continued in the distaff line as a branch of the House of Habsburg.
