How did Karl Marx change socialism?

Karl Marx transformed socialism by introducing a scientific approach to social theory, emphasizing the role of class struggle and economic systems in shaping society. He critiqued earlier socialist ideas, advocating for a revolutionary overthrow of capitalism rather than gradual reform. His analysis of capitalism's dynamics, particularly in works like "The Communist Manifesto" and "Das Kapital," laid the foundation for Marxist theory, which posits that history is driven by material conditions and class conflicts. This shift towards a more systematic and revolutionary framework significantly influenced various socialist movements and ideologies worldwide.