The Jagiellon Era of 1385–1569 refers to the union of
Poland with
Lithuania by the Lithuanian grand duke
Jogaila. The partnership proved profitable for the Poles and Lithuanians, who played a dominant role in one of the most powerful empires in Europe for the next three centuries.
The election of Jagiello to the Polish throne raised up a host of enemies against him. The Teutonic Knights, already weakened by internal dissensions, saw their whole position menaced by the union of Poland and Lithuania. The conversion of Jagiello and of Lithuania (officially, anyway) to Christianity took away the nominal mission of the Order and reduced its warfare to political aggression pure and simple, and the great strength of the Lithuano-Polish state was a serious menace to its political supremacy, especially as the Hundred Years' War and the Hussite movement, both now at their height, drew German fighting men to the West and deprived the Order of reinforcements. Thus threatened, the Order used all its diplomatic skill to break up the union by making trouble between Jagiello and his cousin, Vytautas of Lithuania, who, though he greatly admired Jagiello personally, was opposed to him by every political consideration, and was the natural center of all the disaffection to the union that existed in Lithuania. Jagiello had caused the death of his uncle, Witowt's father, in order to secure the Lithuanian throne, using for this purpose the services of the Teutonic Order – ever ready to promote dissension among its neighbors. Witowt, ambitious and very able, both as a statesman and a soldier, had himself aspired to the throne of Poland, and failing that, had determined to keep Lithuania separate, raise it to a kingdom, and rule it himself. He was supported in this ambition, not only by the Teutonic Order and by Sigismund I the Old, but also, probably, by the majority of the Lithuanian nobility. Their opposition to the union was both political and religious. Religiously, though Lithuania proper was officially Roman Catholic, in fact she was still more than half pagan, while the province of Samogitia was frankly pagan and remained so for a long time. The rest of the territory – that conquered from Russia, which was five sixths of the whole – belonged to the Eastern or Greek Orthodox Church, and was almost as hostile to Roman Catholicism as to paganism.
Since the Greek Church is so important an element in Polish history, a word regarding its history is perhaps in place. Originally, the Catholic Church was one. Each bishop was supreme in his own diocese and subject to no superior authority except the General Church Councils, When, however, the Roman Empire broke into two parts, the Eastern and the Western, as a result of the barbarian invasions, the two branches of the Church developed very differently. The Church of the West was very strongly influenced by Roman law. Changes in its creed, in its ritual, and also the increasing claims of the Bishop of Rome to supremacy over the other bishops, and finally over the world, completely estranged the Eastern Church and led to its rejection of the authority of the Councils where these matters were decided in favor of the West. It continued its existence as a separate Church, composed of the patriarchates (or archbishoprics) of Antioch, Alexandria, Jerusalem, and Constantinople. Although no one of these ever attained a supremacy over the others at all comparable to the supremacy of Rome in the West, yet Constantinople being the capital city and the residence of the Emperor, its patriarch did acquire an influence and a prestige much greater than that of the other patriarchs.
It was from the Church at Constantinople that the missionaries were sent who Christianized Russia and from Constantinople the Russians derived, not only their religion, but their learning, their art, their philosophy, and their whole civilization. The culture which they developed had thus a strong Oriental strain based as it was upon Byzantine tradition. On the other hand, the fact that the Poles were Roman Catholics meant that their civilization was essentially Roman and Teutonic in origin. This difference has been the basal reason for the age-long antagonism of these two greatest, and, geographically, most closely connected, of Slav peoples. From the very moment of her conversion, Orthodoxy has been an integral part, a necessary characteristic, of Russian nationalism, and opposition to the one has been, from the Polish point of view, necessarily opposition to the other. All the old-Russian part of Lithuania was thus steadily opposed to any union with Roman Catholic Poland.
