Final answer:
Karl Marx left his homeland, Germany, due to political pressures after the failure of the Revolutions of 1848, which was contrary to the changes he advocated in The Communist Manifesto. He continued to develop his critiques of capitalism while in exile in London, with his theories not realizing as predicted in Germany, but eventually taking hold with the Russian Revolution in 1917.
Step-by-step explanation:
Karl Marx, the German-born philosopher and economist, had to leave his homeland due to political pressures arising from his revolutionary ideas. The decisive event that led to his exile was the failure of the Revolutions of 1848, a series of widespread uprisings across Europe that sought to overthrow the prevailing conservative political order. Marx, having published The Communist Manifesto with Friedrich Engels in the same year, found his ideas in direct conflict with the interests of the ruling classes. Moreover, his expectations for a workers' revolution were not realized in Germany. Instead of Marx's vision materializing, his homeland moved towards a social democracy that aimed for a gradual transition from capitalism to socialism without a violent overthrow of the system.
Consequently, Marx settled in London where he continued his work and further developed his critique of capitalism, which was encapsulated in his seminal work, Capital. Marx's predictions that a socialist revolution would first occur in the most advanced industrial nation, England, did not come to pass. Instead, the eventual successful revolution occurred in Russia in 1917, deviating from Marx's forecasts and leading many to question the validity of his theory known as dialectical materialism.