Marx's ideas mainly impacted on people after the Industrial Revolution, when industrial capitalism had reached an advanced stage. Nevertheless, the Industrial Revolution was crucial for the development of Marxism in that it provided Marx with the raw material—the inspiration—for his ideas.
This particular period of history was characterized by rapid, sudden change. There was mass migration from the countryside to the burgeoning towns and cities, where people found work in the new industries. Marx welcomed this development, as he saw it as an improvement on the old economic system, a system based upon agriculture. At the same time, he acknowledged the great suffering and poverty that the Industrial Revolution brought to the growing urban working class, or the proletariat, as he called them. Working conditions in the new factories were appalling; pay was low, and workplace accidents were frequent.
Marx set out to change things through his writings and his political activity, arguing and agitating for a new economic system—communism—that would replace what he regarded as the inhumanity and exploitation of capitalism. In Marx's lifetime, his ideas provided inspiration to countless working men and women, giving them a sense of hope that they would one day overthrow the existing system. However, it wasn't until long after the Industrial Revolution had passed into an advanced stage of capitalism, and many years after Marx's death, that the impact of his ideas began to be fully felt on millions across the globe, when socialist revolutionaries started to put those ideas into practice.