The Belorussians, whose lands had been incorporated…

The Belorussians, whose lands had been incorporated into the expanding Grand Duchy of Lithuania after the disintegration of Kievan Rus' in the thirteenth century, at first exerted a strong religious and cultural influence on the pagan Lithuanians; but the position of the Orthodox Belorussians began to decline after the dynastic union of Lithuania and Poland in 1386 and the Lithuanians’ consequent conversion to Latin Christianity.