Knight v Knight (1840) 49 ER 58 is an English trusts law case, embodying a simple statement of the "three certainties" principle. This has the effect of determining whether assets can be disposed of in wills, or whether the wording of the will is too vague to allow beneficiaries to collect what appears on the face of the will to be theirs. The case has been followed in most common law jurisdictions.
^Burke's Genealogical and Heraldic History of the Landed Gentry, 15th Edition, ed. Pirie-Gordon, H., London, 1937, p.1306, pedigree of Rouse-Boughton-Knight of Downton Castle, 1st quarter. Blazoned similarly for their cousins Knight of Wolverley, Worcestershire, in: Victoria County History, Worcestershire, Vol.3, 1913, Parishes: Wolverley, pp.567-573 as: Argent, three pales gules in a bordure engrailed azure on a quarter gules a spur or (Victoria County History, Worcestershire, Vol.3, 1913, Parishes: Wolverley, pp.567-573)