The Treaty of Trestahn was ratified in 2402 by the Lyran Star Empire and the U'lanna Commonwealth, a treaty that set forth conditions under which the U'lanna, brought back from extinction, was allowed to re-settle its ancestral homeworld. It also marked the de jure end of the U'lanna Campaign. It was brought to a referendum, ratified 1,255 votes to 557. (Star Trek: The Stoneship Files: "For a New World")