Lord Cottenham was a significant legal figure in nineteenth-century Britain. He was a Lord Chancellor and Keeper of the Great Seal in both Lord Melbourne's and Lord Russell's administrations. Yet compared with his peers he has faded into obscurity, because his contribution to the reform of the Court of Chancery and the development of the law, particularly equity, has not been fully appreciated. It will be argued that Lord Cottenham was not as successful as his successors in reforming Chancery because his attempts to do so were flawed by the view that incremental reform would redress the problems which beset the Court. However, he made some highly significant contributions to equitable doctrine, sometimes taking a practical approach to judicial decision-making and laying the foundation for some modern doctrines.