Getting the title right
Lithuania is often called the last pagan state in Europe, and there is truth in that. The ruling elite did not formally accept Latin Christianity until 1386, and some of the population in the west of the country, Samogitia, was converted later, in the early fifteenth century. But the phrase needs care. Lithuania was a Grand Duchy, not a kingdom, for almost all of the period. Only one ruler, Mindaugas, was crowned king, in the early 1250s, and the kingdom did not last. Also, many Lithuanians, especially in the Rus lands the state absorbed, were already Orthodox Christians. So “Europe’s last pagan state” is a handy summary, not a strict description.
Before the state
The Lithuanians were a Baltic-speaking people, related to Latvians and the now-vanished Old Prussians, and living in the forests and marshes between the Neman River and the Daugava. Their religion honored natural features and a range of pagan gods, among them a thunder god often linked with Perkūnas, and sacred groves, fire and the cult of ancestors. Our knowledge of these beliefs comes largely from hostile Christian writers, so details are uncertain.
Early on they lived in small chiefdoms. In the thirteenth century pressure from outside seems to have pushed these toward unification. German crusading orders, notably the Livonian Brothers of the Sword and later the Teutonic Knights, were conquering Baltic peoples to the north and west, and Lithuanian leaders needed to organize defense and war bands.
Mindaugas
Mindaugas emerged as the leading figure around the 1230s and 1240s. He reached an agreement with the Livonian branch of the German order and accepted baptism, and in about 1253 was crowned king with papal approval. This gave him protection against crusaders. But he apparently remained unpopular with many of his people, and after he turned on relatives and nobles he was killed in 1263. His kingdom collapsed, and Lithuania returned to paganism and to leadership by grand dukes.
Growth into a large state
The Grand Duchy then grew steadily. A key figure is Gediminas, who ruled in the first part of the fourteenth century and is credited with building up its power and founding the later capital at Vilnius. He wrote to Western rulers and church officials, at times hinting at conversion, and used diplomacy skillfully against his neighbors. His sons Algirdas and Kęstutis later divided leadership, Algirdas looking east and Kęstutis facing the Teutonic Knights in the west.
The expansion was largely into the former lands of Rus. The old Rus principalities were weakened after the Mongol invasion, and Lithuanian rulers took many of them, sometimes by conquest and sometimes by agreement or marriage. Much of the population there was Orthodox, and the Lithuanian rulers generally allowed their religion, law and language to continue. In fact Old East Slavic became a major language of the Grand Duchy’s chancery. At its largest, around the early fifteenth century, the state stretched from near the Baltic Sea toward the Black Sea, though the southern reach was loose and its borders are debated. The Golden Horde was the main steppe power to the south and east, and Lithuania contested territory with it.
Why conversion came late
For a long time the pagan rulers had good reasons to resist. The crusading orders attacked them using the language of religious war, and baptism offered no guarantee they would stop. In practice conversion could mean submitting to the order’s authority. Lithuanian leaders could also bargain: they promised baptism to Western rulers at moments of need without actually going through with it, and the Teutonic Knights’ campaigns, which brought knights from across Europe on seasonal expeditions, were a regular feature of the border.
Jogaila and the union with Poland
The turning point came when Jogaila, a son of Algirdas, sought support in a succession struggle against his uncle Kęstutis and cousin Vytautas. At the same time, the Polish nobility needed a husband for the young ruler Jadwiga. In 1385 an agreement at Krewo laid out terms, including Jogaila’s baptism and marriage to her. He was baptized in 1386 as Władysław and became king of Poland, while remaining the leading ruler in Lithuania. A dynastic link now joined two very different states.
Conflict with Vytautas ended in a settlement that made him grand duke under Jogaila’s overlordship. Vytautas ruled until 1430 and is remembered as one of Lithuania’s greatest rulers. Lithuanian and Polish forces fought together at the Battle of Grunwald in 1410, where the Teutonic Knights suffered a heavy defeat. The Samogitians were formally baptized soon afterward, and the order lost its stated justification for war against Lithuania.
What changed
After conversion the Grand Duchy remained distinct, with its own offices, laws and nobility, though ties with Poland deepened over the following centuries. Its story shows that medieval Europe’s religious borders moved slowly and that a pagan power could defend itself for generations, partly by turning its enemy’s holy war into a political struggle.