An epochal transformation of nature-society relations was inscribed in the transition from feudalism to capitalism. This article advances three central propositions. First, the origins of today’s global ecological crisis are found in the emergence of the capitalist world-economy in the “long” sixteenth century - not in industrialization, population growth, or market expansion, as the conventional wisdom would have it. Secondly, the crisis of feudalism was a general crisis not only of medieval Europe’s political economy, but in equal measure an expression of feudalism’s underlying ecological contradictions. Thirdly, the rise of capitalism effected a radical recomposition of world ecology. As early as the sixteenth century, we can see how the emergent logic of capital, which at once implies endless expansion and seeks to flatten socio-ecological diversity, undermined the possibilities for a sustainable relation between nature and society. Capitalism thus differed radically from feudalism and all other precapitalist formations. Where earlier ecological crises had been local, capitalism globalized them. From this standpoint, the origins of capitalism may shed light on today’s ecological crises.