The Cartethi Calendar consists of thirteen months, each divided into three marches composed of nine days each, for a total of 351 days a year. These reflect the orbit of Feilt’s smaller moon, Pirellis, which cycles through the sky every 27 days, and the larger moon Feris, which cycles once per nine days.
Cartheth’s months are named for the elder Perian gods, and are in order:
Each month is separated into three marches, known traditionally as the Qur, the Homp, and the Ond, respectively. The days within each march were at one time denoted by a combination of the name of the march and the number of the day, such as the Qur’un or Ondtre. This frequently caused problems when arranging business across borders, however, and in the early 10th century many scholars and merchants began using a system that simply denoted the year, month, and day of the month, i.e. 1664/7/22