In a 1991 article for the Journal of World History, David Christian argued that world historians should widen the temporal and disciplinary scope of their field to take in current scientific theories about the origins of life, the planet and even the Universe. Since then, 'big history' as he coined it has become the subject of vibrant historiographical discussions in teaching and research programs in Australia, the United States, Russia and the Netherlands. In this article, I trace the emergence of big history over the last fifteen years and explore the varied theoretical propositions of its practitioners. Further, I demonstrate that, far from being a new branch of world history, big history can be usefully located in the ancient and long-lived tradition of universal history writing.