Marx is recognised by friend and foe alike as a great "thinker". But what crystallized his worldview and approach wasn't solely his intellectual development from independent study. It was also his role as a political activist. In 1848, in the immediate aftermath of the publication of the Communist Manifesto, momentous revolutions broke out across all of Europe against feudal absolutism and for Democracy. Marx and Engels played a leading role in these revolutions in Cologne, one of the most left-wing cities at the time. Their intervention into the 1848 revolutions and the political lessons they drew from the experience were vital to guiding future generations of revolutionaries. Some of these lessons remain timeless and vital for socialists to carry on today.