Why do armies often fail to transmit and coherently apply lessons from their past? Using the concept of ?layered organizational culture?, this article formulates a pioneering theoretical argument to explain how military organizations learn from their historical experience. Analysing empirical material from internal debates within the British Army, the article observes an inherent incompatibility between lessons gleaned from, on the one hand, the Anglo-Afghan Wars and, on the other hand, British counterinsurgency campaigns after 1945. This is less a result of actual differences in the external context but of changing organizational ?filters?: different layers of military organizational culture result in different ways of selecting and transmitting relevant lessons from warfare experience. Older and newer cultural layers can interact and thus contribute to incoherent strategy-making in the present. This argument is illustrated by reviewing the layering process within the British Army since the 19th century. The article shows a shift from emphasizing the specificity of local contexts towards the application of universal principles. This has contemporary relevance: co-exisiting yet incompatible historical lessons contributed to significant incoherence in operational strategy during the initial months of the British deployment in Afghanistan in 2006.