State religion of the Lithuanian principality in the XIV centuries.

Correct answer: Catholicism.
In the 13th century, the Lithuanian prince Mindovgas (Mindovg) was forced to accept the Catholic faith and the crown from the Pope, who declared him the ruler of the Kingdom of Lithuania. This was due to the hostilities against the German orders of knighthood. However, in 1261 he renounced his faith in Christ and expelled the Roman bishops. Until 1389 Lithuania was officially a pagan state, despite the fact that its leaders professed Christianity. But in 1387 Jagiello began to baptize the nobility and pagan regions, and in 1389 Lithuania officially became Christian.