As a political philosophy, communism was codified by Karl Marx's seminal role while he lived in Brussels; he claimed that private property only existed when society made it possible to gain a surplus of goods. In his view, this was an unfair distribution of a finite system of goods and services; Marx railed against the Rich, claiming that they were unfairly keeping wealth away from the Poor. Elements of communism have existed in various forms for centuries in varied locales, including Rome, Iran, France and some Church communities.
Communism is a political philosophy which holds that private property is an unworkable concept. Instead, all goods and services should be held and distributed according to the need of the common good; this is best summed up in Karl Marx's infamous motto: "From each according to his Ability, to each according to his Need." In other words, every person who can contribute to the common good should do so to the best of their ability, while every person in society should be allowed a quota of goods according to their need. The common good is held above all else, and the individual is only of worth in their ability to contribute to that common good.
Communism was practiced in various countries worldwide over the 19th and 20th centuries, and generally failed to create the Socialist Utopia that Marx envisioned. The most successful current example of a Communist country is China, but many commentaries point to China's success as the result of capitalist instead of communist ideals.