The Jagiellons (Lithuanian: Jogailaičiai, Polish: Jagiellonowie) were a royal dynasty originating from the Lithuanian House of Gediminas dynasty that reigned in Central European countries (present day Lithuania, Belarus, Poland, Ukraine, Latvia, Estonia, parts of Russia (including nowadays Kaliningrad oblast), Hungary, Czech Republic, Slovakia) between the 14th and 16th century. Members of the dynasty were Grand Dukes of Lithuania 1377–1392 and 1440–1572, kings of Poland 1386–1572, kings of Hungary 1440–1444 and 1490–1526, and kings of Bohemia 1471–1526.
The dynastic union between the two countries (converted into a full administrative union only in 1569) is the reason for the common appellation "Poland–Lithuania" in discussions about the area from the Late Middle Ages onwards. One Jagiellonian briefly ruled both Poland and Hungary (1440–44), and two others ruled both Bohemia (since 1471) and Hungary (1490–1526) and then continued in distaff line as the Eastern branch of the House of Habsburg.
The name (other variations used in English include: Jagiellonians, Jagiellos, Jogailos, Jagiellas) comes from Jogaila (Polish: Jagiełło), the first Polish king of that dynasty. In Polish, the dynasty is known as Jagiellonowie (singular: Jagiellon, adjective, used of dynasty members, also patronimical form: Jagiellończyk); in Lithuanian it is called Jogailaičiai (sing.: Jogailaitis), in Belarusian Яґайлавічы (Jagajłavičy, sing.: Яґайлавіч, Jagajłavič), in Hungarian Jagellók (sing.: Jagelló), and in Czech Jagellonci (sing.: Jagellonec; adjective: Jagellonský), as well as Jagello or Jagellon (fem. Jagellonica) in Latin. In all variations of that name, the letter J should be pronounced as in "Hallelujah" (or as Y in "yes"), and G – as in "get".
Gediminids (Lithuanian: Gediminaičiai), the immediate predecessors of the first Jagiello, were monarchs of the medieval Lithuania with the title didysis kunigaikštis which would be translated as Mighty King according to the contemporary perception. The later construct for its translation is Grand Duke (for its etymology, see Grand Prince). Their realm, the Grand Duchy of Lithuania,was chiefly inhabited by Lithuanians and Ruthenians, and was at least half-Slavic.
Jogaila, the eponymous first Jagiello ruler, started as the Grand Duke of Lithuania. He then converted to Christianity and married the 11-year-old Jadwiga, the second of Poland's Angevin rulers, and thereby becoming himself King of Poland, founded the dynasty. At the time, he called himself King Władysław, without an ordinal number, but later historians have referred to him as Władysław II (of Poland), V (of Lithuania) or sometimes Władysław II Jagiello of Poland and Lithuania.
The rule of Piasts, the earlier Polish ruling house (c.962–1370) had ended with the death of Casimir III.
Jagiellons were hereditary rulers of Lithuania and Poland.
The Jagiellon rulers of Lithuania and Poland (with dates of ruling in brackets) were: