What factors gave rise to socialism?

Socialism is strongly correlated to the rise of industry and reorganization in the division of labour. By the first half of the 19th century, Industrialization became highly common in Western Europe and the United States. With a rise in urbanization, or a mass migration to cities saw an influx of people seeking better opportunities for work in manufacturing. These jobs were tied into heavy machinery, psychically exhausting hours, and provided little pay.

In parallel to first half of the 19th century which saw the rise in Industry, thinkers came forward in response with concepts of utopias and ideologies that catered toward better rights and privilege for the middle class. One famous example is Karl Marx, widely considered an influence in socialism and communist thought, who stated that as creators of the means of production, workers should assume leadership for a society that doesn't marginalize the worker and fairly distributes the means of production from workers in more classless society. 

Through these thoughts and various socialist propaganda, workers protested for more rights and better conditions in various places through industrial Europe and the United States all throughout the 19th century.