) occurred in 1387, initiated by King of Poland and Grand Duke of Lithuania Władysław II Jagiełło and his cousin Vytautas the Great.
It signified the official adoption of Christianity by Lithuanians, the last pagan nation in Europe.
This event ended one of the most complicated and lengthiest processes of Christianization in European history.
Their subordinates and the people followed their example, borrowing, for instance, many of the East Slavic versions of Christian names in the 11th - 12th centuries.
Jogaila's Russian mother urged him to marry Sofia, daughter of Prince Dmitri of Moscow, who required him first to convert to Orthodoxy and to make Lithuania a fief of the Grand Duchy of Moscow.
That option, however, was unrealistic and unlikely to halt the crusades against Lithuania by the Teutonic Order.
Jogaila sent Dobrogost, Bishop of Poznań, as ambassador to Pope Urban VI with a petition for the erection of an episcopal see at Vilnius and the appointment of Andrzej Jastrzębiec to fill it. The baptism of nobles and their peasants was at first carried out in the capital Vilnius and its environs.
The nobility and some peasants in Aukštaitija were baptized in spring, followed by the rest of the Lithuanian nobility.