or Calends, in the Roman chronology, the first day of every month.—The word is formed from καλέω, I call or proclaim; because, before the publication of the Roman fasti, it was one of the offices of the pontiffs to watch the appearance of the new moon, and give notice thereof to the rex sacrificulus; upon which a sacrifice being offered, the pontiff summoned the people together in the Capitol, and there with a loud voice proclaimed the number of kalends, or the day whereon the nones would be; which he did by repeating this formula as often as there were days of kalends, Calo Juno Novella. Whence the name calende was given thereto, from calo, calare. This is the account given by Varro. Others derive the appellation hence, That the people being convened on this day, the pontifex called or proclaimed the several feasts or holidays in the month; a custom which continued no longer than the year of Rome 450, when C. Flavius, the curule sedile, ordered the fasti or kalendar to be set up in public places, that everybody might know the differences of times, and the return of the festivals.

The kalends were reckoned backwards, or in a retrograde order. Thus, v. g. the first of May being the kalends of May; the last or the 30th of April was the pridie kalendorum, or second of the kalends of May; the 29th of April, the third of the kalends, or before the kalends; and so back to the 13th, where the ides commence; which are likewise numbered invertedly to the fifth, where the nones begin; which are numbered after the same manner to the first day of the month, which is the kalends of April. See IDES, and NONES.

The rules of computation by kalends are included in the following verses:

Prima dies mensis cujusque est diēs kalendae: Sex Maius nonas, Octōber, Iulius, ei Mars; Quattuor ad reliquos: habet idem quilibet octo. Inde dies reliquos omnes dic effer kalendas; Quas retro numerans dices a mensē sequente.

To find the day of the kalends answering to any day of the month we are in; see how many days there are yet remaining of the month, and to that number add two: for example, suppose it the 22d day of April; it is then the 10th of the kalends of May. For April contains 30 days: and 22 taken from 30, there remain 8; to which two being added, the sum is 10. The reason of adding two is, because the last day of the month is called secundo kalendae, the last but one tertio kalendae, &c.

The Roman writers themselves are at a loss for the reason of this absurd and whimsical manner of computing the days of the month: yet it is still kept up in the Roman chancery; and by some authors, out of a vain affectation of learning, preferred to the common, more natural, and easy manner.

Kalends are also used in church history to denote conferences anciently held by the clergy of each deanery, on the first day of every month, concerning their duty and conduct, especially in what related to the imposition of penance.

Kalends of January, in Roman antiquity, was a solemn festival consecrated to Juno and Janus; wherefore the Romans offered vows and sacrifices to those deities, and exchanged presents among themselves as a token of friendship.

It was only a melancholy day to debtors, who were then obliged to pay their interests, &c. Hence Horace calls it triflex kalender; Lib. I. Serm. Sat. 3.