Lithuanians in 1387 and Western Lithuanians, or Samogitians, in 1417 were the last in Europe to accept the Roman Catholic faith. They did not go through the Middle Ages. Until then Lithuanians had worshiped their own pagan gods related to the cosmos, natural phenomena (fire worshipping), nature and wildlife. The pagan faith was an animalistic religion imposing spirituality on the living and non-living nature. There was nothing particularly Lithuanian in it, as it was the religion of the ancient pre-Christian Europe.
The first Christian missions reached the Balts, or Aistians (aestiorum gentes), as late as in the 10th through 12th centuries. Missionaries visited Western Balts: Bishop Wojciech Adalbert of Prague was killed in 997 in Prussia; the German missionary Archbishop Bruno of Querfurt (St. Boniface) was killed in 1009 by the Yotvingians; the German Bishop Meinhard was consecrated as the Bishop of Livonia in 1186, and the second Bishop of Livonia Berthold, the Abbot of Saxony, barely managed to get away from the Daugava estuary in 1197 and escape death. [He perished in a battle with the Livonians in 1198]. Pope then proclaimed a crusade, and Albert, the third Bishop of Livonia, arrived with military force in 1200. This was how the wars of the crusade started at the eastern coast of the Baltic Sea.
During the crusade in Palestine the Teutonic Order (Ordo Theutonicorum Sanctae Mariae Dei Virginis) was established in 1190. In 1226 the Polish (Masurian) Duke Conrad invited the knights of the Order and granted them a small province of Kulm (Chelm) on the Vistula. He was hoping to use them in the fight against the pagan Prussians. The European rulers Emperor Frederick II (1226) and Pope Gregory IX (1230) approved the gift. In 1234 the Pope took the Order “in ius et proprietatem beati Petri” and gave all pagan Prussian lands “in veram et perpetuam proprietatem possidendum pleno iure” to it. The statement was reiterated by the popes Urban IV in 1263 and Clement IV in 1268. This laid the foundation for the state of the Teutonic Order. Pope Innocent IV divided all Prussian lands into four dioceses in 1243, granting them one third of the Prussian land and two thirds of the lands to the Order. In fifty years all Prussian lands from the Vistula to the Nemunas were conquered by the Order. The Prussian tribes were subordinated to the power of the Order and christened against their will. In 1283 the cruellest war of the Order against the pagan Lithuanians started and continued for over a hundred years. The objective of the war thrust upon Lithuanians by the Order was to establish their own state.
In the middle of the 13th century a pagan Lithuanian state was formed. It fought a war of life and death against the Order. The Order sought to gain control of the country and then convert the population without granting the new Christians any political or social rights. This brought about wide resistance of the population. The Order colonised the occupied Prussian lands, created public institutions and defence system. In the warfare against the pagans, the Teutonic knights burned their farms and villages, killed the old and the young, took the stronger men and women into captivity and took away their livestock. In the 14th century the knights carried out approximately 100 military campaigns in Lithuania, while Lithuanians waged twice as few campaigns in Prussia. The climax of the war reached in the latter half of the 14th century, yet it did not bring a victory to either side. The Lithuanians managed to push the Tatars out of their Ukrainian and Belarussian territories, annexed these lands and acquired a huge military power in their opposition against the Order.
The pagan and Christian faiths were not at war. By that time Franciscan and Dominican monasteries had already been established in Lithuania with Lithuanian monks. Therefore, it was a war of political and social nature waged on a religious pretext. In this war the knight monks had the military power recruited from Germany and volunteers from all over Europe who were looking for adventure, knightly entertainment, titles, indulgences and plunder. Their tactics consisted of repetitive military raids. Their justification was the pagan lands given to them by popes and emperors (in 1337 Emperor Louis gave the whole of Lithuania to the Order). The war that the Order thrust upon the Lithuanians and their relatives was cruel, unreasonable and senseless.