The Word “Capitalism” was coined as an insult by Karl Marx, but the free market that is now called Capitalism existed for thousands of years before that in various forms. The Roman empire was a trading empire as much as it was an imperialist power. It is true that in the middle ages Feudalism handicapped the free market by hampering freedom and locking people into peasant classes, but limited trade continued of a capitalist kind. The renaissance led to the Feudal Aristocrats being replaced by businessmen as leaders of the modern world, and an explosion of science, technology and wealth resulted.
Socialism redistributes wealth in ways that work against the growth of wealth, removing incentives for wealth creation. Capitalist free Markets on the other hand are designed to match supply and demand, to produce wealth, and Capitalism has lifted billions of people out of poverty in the last century. These are just facts.