The Calens (Latin calendae "the called", singular -arum), correspond to the first days of each month of the Roman calendar. The Romans assigned these calends to the first day of the month, signifying the start of the new moon cycle. On that day, the pontiffs would announce at the Curia Calabra the rest days for the upcoming month, and the debtors had to pay off their debts that were inscribed in the calendaria, a sort of accounts book. The date (in this calendar system) was measured relative to days such as the Calends, Nones or Ides, for example, in modern terms, three days past Calends would be the 4th of the month. This sort of system would be used to date documents, diary entries, etc.