A Treaty was a common name for a M'Tar or Na'arbi Liaison or Link. Each Liaison or Link represented a treaty between the M'Tar and Na'arbi in their war against each other throughout history and time. (Star Trek: The Cantabrian Expeditions: "White Flag") While the concept of Treaties was first mentioned in "Lady Lazarus", it wasn't explained until "White Flag". The name and concept are a nod-of-the-hat to Elizabeth Knox's novel, The Vintner's Luck.