Framing the “Oldest Alliance”: Treaty-Making in Fourteenth-Century England and Portugal

Few treaties before the Peace of Westphalia are likely to have affected popular culture as much as the so-called Treaty of Windsor, celebrated in 1386–87 between the rulers of England and Portugal, which has commonly been hailed as the oldest diplomatic alliance in place worldwide. A lesser-known fact is that the Treaty of Windsor was the last of four treaties signed in a relatively short span of 33 years, beginning in 1353. This essay examines each of those compositions’ context, making, content, and constitutional significance once they came into being. Considering the ever-changing political developments of the Hundred Years’ War and parallel Anglo-Portuguese commercial interests, which ran deeper, ultimately this essay questions the significance of late medieval treaties and the Anglo-Portuguese alliance as a political creation.