As the cases of the Jesús, Maria, y José and the San Juan Baptista made their way through the High Court of Admiralty, the arguments that would eventually be laid before the Court of Prize Appeal took shape. This chapter examines the arguments made in each case and how they affected Anglo-Spanish negotiations over neutrality. The chapter also focuses on the debates between British and Spanish ministers about the meaning and interpretation of the Anglo-Spanish Treaty of 1667 which governed Spanish neutral rights. It introduces two key people in Anglo-Spanish negotiations, Felix D’Abreu (Spanish representative in London) and Sir Benjamin Keene (British ambassador to Spain). Both men would be instrumental in shaping the debates on Spanish neutral rights and whether those rights could be protected through decisions handed down by the Court of Prize Appeal.