The main purpose of the Schlieffen Plan in World War I was to ensure a swift victory for Germany against France before turning its military efforts to Russia. Created by General Alfred von Schlieffen, the plan aimed to avoid a two-front war by invading France through neutral Belgium, securing a quick defeat by capturing Paris. The plan relied on rapid movement and coordination of forces to overwhelm French defenses. However, when the plan faltered due to logistical challenges and the unexpected resilience of the Allies, it contributed to a protracted war marked by trench warfare on the Western Front, altering the war's direction significantly.