Humans and Xi'an first made contact in SEY 2530 (MXY III.838) when Gaia Planet Services (GPS), a United Planets of Earth (UPE). Once the UPE capitulated to the Xi'an Empire's terraforming corporation, attempted to set up operations in the Th.us'ūng system. Because GPS had illegally entered the system, they neglected to perform the necessary surveys required by law, and were thus unaware that the system was already occupied before they attempted to terraform one of the planets.
This activity nearby attracted Xi'an military forces, who seized control of the facility and GPS personnel. For fifty-seven Standard Earth Days, the Xi'an held the Humans hostage while negotiating for information from the UPE. Once the UPE capitulated to the Xi'an Empire's terms, the hostages were released without harm. However, the distrust sown on both sides marked the beginning of the Xi'an-Human Cold War.