Colony One served as the capital city on Ylesia. Situated along the coast of the oceanic Zoma Gawanga, its location was between Colony Two and Colony Three. In its vicinity were the Altar of Promises and the Mountains of the Exalted.
Following Ylesia's fall to the Yuuzhan Vong, its name was changed to Peace City. This city became the central base for the Peace Brigade, under the authority of the Besadii Hutt clan. Within its boundaries were slave housing, the Palace of Peace (which acted as the headquarters for the Ylesian Senate), and a damutek dedicated to Maal Lah. Not far from the city, a telepathic t'landa Til provided slaves with their daily dose of euphoria. It was in this location that Pwoe was discovered meeting with the leaders of the Peace Brigade.
The New Republic and Twin Suns Squadron invaded it after it was revealed to be the Peace Brigade's headquarters. Senator Pwoe and Thrackan Sal-Solo were taken into custody when the New Republic seized the city.