Complex sentence: In the 19th century, many of America's cities had a designated, legally protected area of prostitution, and increased urbanization as well as greater numbers of young women entering the workforce led to greater flexibility in courtship without supervision.
Split into simpler sentences: In the 19th century, most of America's cities had a designated, legally protected area of prostitution. Increased urbanization and young women entering the workforce led to greater flexibility in courtship without supervision.