The topic of this article is the theoretical basis of early English courts for the protection of trademarks from 16th to 19th centuries. This article specifically deals with five historical cases: Sandforth case (1584), Souther v. How (1618), Blanchard v. Hill (1742), Sykes v. Sykes (1824), and Leather Cloth Co. v. American Leather Cloth Co. (1863). After examining those cases and academic materials analyzing the cases, this article found the meaning of each case as follows: First, ‘Sandforth case’ provides with important information that the protection against trademark counterfeit was already established at the municipal or local courts, and the customs of those courts had often been accepted by the common law courts in the 16th century. Second, ‘Blanchard case,’ the first reported English decision clearly involving a claim based on use of a party’s trademark, shows why it was difficult for judges to hold that the court’s jurisdiction over a counterfeit mark was based on the property right in the mark. In the sixteenth and seventeenth centuries, English kings intervened regularly to protect marks by granting charters for exclusive uses of a particular mark for royal revenue. This made English law slow to develop property protection for trademarks. Third, ‘Sykes case’ is the first reported case squarely involving the protection of trademarks by the English common law court. And it is also the first case that the common law court held in favor of the plaintiff, the trademark holder, on the basis of the tort of deceit. Fourth, ‘Leather Cloth case,’ for the first time, based the jurisdiction of the court of equity on property. It held that fraud in the Defendant is not necessary for the exercise of that jurisdiction. And ultimately, the common law court accepted the equity court’s property approach.