Complex sentence: After Partitions of Poland (late 18th century), it belonged to Russian-controlled Congress Poland, and some time in the 19th century, it became to be associated with another Polish region, Podlachia.
Split into simpler sentences: After Partitions of Poland (late 18th century), it belonged to Russian-controlled Congress Poland. Some time in the 19th century, it became associated with another Polish historical region, Podlachia.