Who were the Bolsheviks and what did they believe in?

The Bolsheviks were one of the parties in the Russian Social Democratic Labor Party (the Communist Party)

The RSDLP (from which the Bolsheviks eventually split from) was a group of social and political reformers that believed in Karl Marx's philosophy.

The important parts of Marx's theory as it applied to the Bolsheviks were that:

1) Confict theory - Marx believed that history was formed by the conflict of classes (hunter/gatherers versus agriculturalists, serfs versus lords, capitalists versus socialists, etc.), and that any meaningful social change could only be brought about through conflict.

2) Labor theory of value - In Marx's economics, a good is only as valuable as the labor put into it, and that capitalists (the people who hold the means of production: capital, land, the tools to work, etc.) do not pay laborers the full value of their work, so the relationship between capitalist and laborer is inherently unequal

3) History - Marx viewed history as an evolution of social systems. Primitive society were the hunter-gatherers and early agriculturalists, who were replaced by feudal society, then by capitalism, and that capitalism will be replaced by communism.