The Tenets of Discipline were a series of writings made by the Vulcan philosopher Surak which all Vulcans subscribed to in their belief in logic. A copy of the Tenets were stolen by the early Romulans when they left Vulcan.
In Second History, Praetor Thea sought to establish a peace between the Romulan Star Empire and the Interstellar Alliance of Planets. To accomplish this, she first needed to end the hostilities from Romulan warriors which she wished to accomplish through Captain Spock of the VSS ShiKahr who was to masquerade as the Praetor and inform them of the Tenets. It was Thea's hope that the teachings of the Tenets would calm the warrior spirit of her people and allow peace to flourish in the alternate timeline. (TOS novel: Killing Time)