Complex sentence: The Bohemian Flats were named because of the high percent of the population which came from eastern Europe; the majority of the families occupying the area were Slovaks, Bohemians, and Germans.
Split into simpler sentences: The Bohemian Flats was named because of the high percent of the population which came from eastern Europe. This was soon overturned and became know as "The Bohemian Flats" because of the majority of the families occupiying the area were Slovaks, Bohemians, and Germans.