The Xi'an-Human Cold War (SEY 2530 - 2793) was a period of military and political tension between the United Empire of Earth (UEE) and the Xi'an Empire. It was sparked from first contact between the two civilizations when in 2530 when a Human terraforming company, acting illegally, attempted to set up operations in the Xi'an system Th.us'ūng and were captured by the Xi'an who discovered them there. Though there was no large-scale combat between the sides, bordering planetary systems became militarized zones. The cold war formally ended with the signing of the Perry Line Pact in 2793.