Complex sentence: In 1784, the total population of the territory of Belgium was approximately 2.6 million, with just 25 percent living in cities, but during the 19th century, the population both expanded and urbanized.
Split into simpler sentences: In 1784, Belgium's population was 2.6 million, with just 25 percent living in cities. During the 19th century, the population both expanded and urbanized.