FASTI (from fasti dies, "the divinely authorized days") were the calendars of the ancient Romans. They are the only known form of a graphical representation of all days of the year from the ancient Mediterranean world. By usually displaying twelve columns of the days of the single months, the fasti offered the standard pattern for Christian calendars from late antiquity and ultimately for all representations of the Julian and Gregorian calendars. The listing of the days was organized by the recurring letters A to H (for a continuous week of eight days) at the beginning of every entry. The main information concerned the juridical character of the day, especially indicating whether it was fas (right) to open processes in front of the Roman praetor or not (nefas). The terminologically divine sanction had other consequences, too: The comitia, the Roman legislative body of the people, could not meet on...