Concerns about rising inequality are making headlines all over the world, from America and Europe to China. Yet current debates and policy proposals focus on the recent past, neglecting the very long sweep of history and the lessons it may hold. This lecture traces the evolution of resource inequality from the Stone Age to the present. Only this long-term perspective reveals the forces that drive inequality and allows us to address a crucial question: in history, which factors were capable of reducing inequality, at least for a while? The answer is surprisingly clear but not at all pleasant: war, revolution and pestilence acted as the main equalizers of income and wealth both in the distant and the more recent past. This finding is of considerable relevance to our engagement with inequality today: we must ask whether fiscal policies that seek to curtail inequality are likely to succeed in the absence of these destructive forces, and what this suggests for the future of global inequality.