The christianization of Europe is a subject we often understand as the arrival of a new faith coming from the middle eastern civilizations, which brought culture, unified Europe under one single faith and ended the barbarian ways of life from the tribes of the old continent. But Europe was already culturally rich, and the many different religions of the Europeans brought them happiness and a better understanding of the world around them, the coming of the christian faith changed what being an European truly meant, and the last pagans of Europe fought alone against their brethren who succumbed to the christian faith. The christianization of Europe took time, but in the Balts (nowadays Lithuania, Latvia, Estonia, and the now extinguished Prussians) it took even longer and their ancient tribal believes remained till late.
The Baltic tribes were among the oldest eastern inhabitants of Europe. In ancient times, they occupied a much larger area than their descendants, the Baltic lands stretched much further to the west, to the eastern shores of the Wysla river (nowadays in Poland territory), as well as further eastwards, about a hundred kms beyond the present Lithuanian and Latvian border with Belarus. The most famous Baltic tribes circa 1200 AD, were the Livonians and the Latgalians to the north of the Daugava River, the Selonians, Semigallians and Curonians to the south of the same river and around the Gulf of Riga, the Lithuanians (Aukstaitians at the hightlands and the Samogitians at the lowlands) and further south the Skalvians, Yotvingians (Sudovians), Galindians and the Prussians and their many tribes.
The conquest of the Baltic tribes began after the Crusades in the Holy Land suffered disastrous setbacks. After the crusaders lost Jerusalem to Saladin and the muslims in 1187 AD, they turned to the last pagan areas in Europe. The first crusaders appeared on the eastern shores of the Baltic sea around 1202 AD and settled in the Daugava delta. They established the castle and the city of Riga, now capital of Latvia. This branch of crusaders was originally called the Brothers of the Sword, later renamed the Livonian Order.
Several hundred km southward, in what is now the Kaliningrad district, another branch of crusaders settled there; it was called the Teutonic Order. They had established in Acre in the Holy Land between 1120 and 1128, the order was centered in Swabia (nowadays southern Germany) after the defeat in Jerusalem in 1187. The remnant of crusaders, with a strengthening from the Germanic-speaking lands, came to Prussia and established strongholds at Konigsberg and Marienburg. They gradually started to occupy the lands of the indigenous Prussian tribes (the Sambians, Bartians, Nadruvians, Warmians etc.). At the first stage the crusaders found some willing assistance. They offered protection to weaker tribes and thus played the indigenous people against each other, this helped them to secure their presence on the shores of the Baltic sea.
In 1236 DC, after the battle of Saule, the northern branch of crusaders suffered a major defeat and consequently merged with their southern cousins. After 1250, those two military states had firmly established themselves and started to make inroads into the neighbouring lands in all directions. They were equally eager to assault not only on the pagan tribes, but the Christian Poles and Russians as well. For more than 200 years, all neighbouring nations regardless of their faith, suffered continuous raids from the militant crusaders.
The Baltic sea has always been the greatest source of amber. Since prehistoric times, amber from the Baltic was found in many places further away from its origin. The Neolithic peoples of nowadays Portugal had trading networks with the Balts and amber is commonly found in ancient neolithic tombs of Central Portugal. Later, the Egyptians also coveted the Baltic amber and so did the Roman Empire. Historically speaking, the motives for this new invasion from the crusaders into the Balts, was to ensure that the trading routes with the Baltic areas continued to provide wealth to the newly formed christian nations as well as a religious opportunity, not only to spread the new faith, but to enslave more people under a single creed. The wealth of the Baltic areas was divided among the christian religious orders under the consent of the roman popes.
Between the years 1250 and 1300 AD, crusaders managed to subjugate most Prussians and Latvians. The tribal chiefs who agreed to convert to Christianity were offered protection and full rights to abuse their people as much as they liked. In 1291, when the Crusader State was expelled form the Holy Land, all the Christian fervour to expand the faith and lands turned on the Balts; it became the central front of the crusades. Ever larger numbers of fighters were drawn from Western Europe. On the other side, however, a concentration of forces also took place. The Lithuanians (the strongest of the Baltic tribes at that time) managed to establish a central rule by the year of 1253. The capital of the new state was established in Vilnius. The Grand Duchy of Lithuania had a rather easy time with crusaders by 1300 and it took the opportunity to expand to the east. The conditions were extremely favourable, the eastern Slavs were suffering from the brutal Mongol-Tatars’ invasions, and were eager to accept the rule of pagan but tolerant Lithuanians. The Lithuanians left their Slavic subordinates more or less to their own devises, demanding only soldiers and limited tributes. By this time the pattern of how crusaders were expanding their influence was settled. At first they would try to convince the tribes to accept the one true God and save themselves from pagan falsehoods, but this seldom worked. At the next stage they would come back with the sword and force submission. This meant they had to accept Christianization or die. Those who agreed to receive the Lord as Saviour would be subjugated to work for the Order or for the Archbishop. Crusaders would explain that subservience to the Lord meant working diligently for his cause, and this meant that a peasant must save none of his efforts on this righteous path.