Karl Marx was born in Germany, exiled to Paris, met there Engels (a life long friend), both again left Paris and went to Belgium and at last they reached to England and lived there life-long where real democracy was prevailed. They began to live, think, analyze, express their ideas freely and frankly staying in the Museum of London. Marx wrote many treatise (articles), essays and writings, the main are the Communist Manifesto (1848) and Das Capital (1867).
Marx was both social scientist and political philosopher. For Marx, matter is the basis of all things, matter is the ultimate truth which brings ideas and changes everywhere. It is the matter or mode of production which created classes. Man is the root cause of all evolution and devolution so state is not natural but artificial association which was created by the creation of classes.