1. Introduction 2. Contractual Mistake in Roman Law 3. Contractual Mistake in English Law 4. The Lack of Contractual Mistake at Common Law and the5. Pothier and the Development of Mistake in English Contract Law 6. Von Savigny and the Development of Mistake in English Contract Law 7. The Creation of Contractual Mistake in Nineteenth-century Common Law 8. Mistake of Identity 9. Mistake after Fusion 10. Summary and Conclusions