In what way did sigmund freud advance our understanding of psychology

He was the founder of psychoanalysis (a movement that popularized the theory that unconscious motives control much behavior).  He was also an early researcher on the topic of cerebral palsy. He published several medical papers on cerebral palsy. He showed the disease existed long before other researchers in his day began to notice and study it.

from the conditions of the working class in england by friedrich engels,the main idea is :

manchester's leaders hoped to oppress its working class to benefit factory owners.