Xi'an Calendar

The [Xi'an](https://robertsspaceindustries.com/galactapedia/article/ReJwN9KJEj-xian) calendar (Modern Xi'an Year, *r.aiXy'an*) is measured by the celestial mechanics of their former homeworld, RyiXy'an (Hyoton III). It differs from the [Human](https://robertsspaceindustries.com/galactapedia/article/0Nwpnr6wa2-humans) calendar in a number of significant ways; for example, each Xi'an year is equivalent to 1.28 Human years, is assigned a number counting upwards from when the current Imperial House ascended to the throne, and is prepended with a number that represents the corresponding [Imperial](https://robertsspaceindustries.com/galactapedia/article/VYLyPxQnpp-emperor-taunuasao-taoyusao) Age. The [First Imperial Age](https://robertsspaceindustries.com/galactapedia/article/VDoPeW55W4-first-imperial-age) began in the Human year 19668 BCE, and was recorded by the Xi'an as I.0 (or 1.0) The current [Third Imperial Age](https://robertsspaceindustries.com/galactapedia/article/R4ZejoYNEY-third-imperial-age) began in the Human year 1457, and was recorded by the Xi'an as as III.0 (or 3.0).