 Berlin’s account was further complicated by combining conceptual analysis with history. He associated negative liberty with the liberal tradition as it had emerged and developed in Britain and France from the seventeenth century to the early nineteenth. He later regretted that he had not made more of the evils that negative liberty had been used to justify, such as exploitation under laissez-faire capitalism; in Two Concepts, however, negative liberty is portrayed favourably, and briefly. It is on positive liberty that Berlin focused, since it was, he claimed, both a more ambiguous concept, and one which had been subject to greater and more sinister transformation, and ultimately perversion.