Socialism, by definition, is a set of political beliefs and principles whose general aim is to create a system in which everyone has an equal opportunity to benefit from the country's wealth, usually by having the country's main industries owned by the state.
The idea of socialism can be traced back into Plato's Republic, Thomas More's Utopia or even the Old Testament. But realistically, modern socialism first appeared around in 1830, by various writers who opposed the social and economic relations and dislocations brought by the Industrial Revolution. Henri de St-Simon, Charles Fourier and Robert Owen first used the term "socialism". Each of them had a great contribution towards the new doctrine. However, none of them can compare to the influence of Karl Marx and his Communist Manifesto.
Modern socialism emerged as the result of modern industrial capitalism and the Industrial Revolution. During the 19th century, the Industrial Revolution transformed Western Europe and North America from agricultural nations to industrial nations. The transformation of these countries' economic structure led to drastic changes in the peoples lifestyle. The average worker went from being a self-employed farmer to being an employee at a large factory. The working class or proletariat was finally formed. As a result of urbanization, cities grew rapidly and over population became an enormous problem. This new industrial workforce, the proletariat, worked and lived in awful conditions. Poverty was rampant due to the high unemployment and the low wages. The transformation affected not only the lives of the workers but also craftsmen who were being compelled to switch jobs because factories could produce the same product at a much lower cost and price.