KALENDAR, a distribution of time, accommodated to the uses of life; or a table or almanack, containing the order of days, weeks, months, feasts, &c. happening throughout the year. See TIME, MONTH, YEAR, &c.
It is called kalendar, from the word kalendæ, anciently wrote in large characters at the head of each month. See KALENDS.
The days in calendars were originally divided into octades, or eights; but afterwards, in imitation of the Jews, into hebdomades, or sevens; which custom, Scaliger observes, was not introduced among the Romans till after the time of Theodosius.
There are divers calendars, according to the different forms of the year and distributions of time established in different countries. Hence the Roman, the Jewish, the Persian, the Julian, the Gregorian, &c. calendars.
The ancient Roman calendar is given by Ricciolus, Stravius, Duret, and others; by which we see the order and number of the Roman holidays and work days.
The three Christian calendars are given by Wolfus in his Elements of Chronology.
The Jewish calendar was fixed by Rabbi Hillel about the year 360, from which time the days of their year may be reduced to those of the Julian calendar.
The Roman KALENDAR owed its origin to Romulus: but it has undergone various reformations since his time. That legislator distributed time into several periods, for the use of the people under his command: but as he was much better versed in matters of war than of astronomy, he only divided the year into ten months, making it begin in the spring, on the first of March; imagining the sun made his course through all the seasons in 304 days.
Romulus's calendar was reformed by Numa, who added two months more, January and February; placing them before March: so that his year consisted of 355 days, and began on the first of January. He chose, however, in imitation of the Greeks, to make an intercalation of 45 days; which he divided into two parts; intercalating a month of 22 days at the end of each two years; and at the end of each two years more another of 23 days; which month, thus interposed, he called Marcedonius, or the intercalary February.
But these intercalations being ill observed by the pontiffs, to whom Numa committed the care of them, occasioned great disorders in the constitution of the year; which Cæsar, as sovereign pontiff, endeavoured to remedy. To this end, he made choice of Sosigenes, a celebrated astronomer of those times; who found, that the dispensation of time in the calendar could never be settled on any sure footing without having regard to the annual course of the sun. Accordingly, as the sun's yearly course is performed in 365 days six hours, he reduced the year to the same number of days: the year of this correction of the calendar.
dar was a year of confusion; they being obliged, in Kalendar order to swallow up the 65 days that had been imprudently added, and which occasioned the confusion, to add two months besides the Marcedonius, which chanced to fall out that year; so that this year consisted of 15 months, or 445 days. This reformation was made in the year of Rome 708, 42 or 43 years before Christ.
The Roman calendar, called also Julian calendar, from its reformer Julius, is disposed into quadriennial periods; whereof the first three years, which he called communes, consist of 365 days; and the fourth, bisextile, of 366; by reason of the six hours, which in four years make a day or somewhat less, for in 134 years an intercalary day is to be retrenched. On this account it was, that Pope Gregory XIII. with the advice of Clavius and Ciaconius, appointed, that the hundredth year of each century should have no bisextile, excepting in each fourth century: that is, a subtraction is made of three bisextile days in the space of four centuries; by reason of the 11 minutes wanting in the six hours whereof the bisextile consists.
The reformation of the calendar, or the new style as we call it, commenced on the 4th of October 1582, when ten days were thrown out at once, so many having been introduced into the computation since the time of the council of Nice in 325, by the defect of 11 minutes.
Julian Christian KALENDAR, is that wherein the days of the week are determined by the letters A, B, C, D, E, F, G, by means of the solar cycle; and the new and full moons, especially the paschal full moon, with the feast of Easter, and the other moveable feasts depending thereon, by means of golden numbers, rightly disposed through the Julian year. See CYCLE, and GOLDEN Number.
In this calendar, the vernal equinox is supposed to be fixed to the 31st day of March: and the cycle of 19 years, or the golden numbers, constantly to indicate the places of the new and full moons; yet both are erroneous. And hence arose a very great irregularity in the time of Easter. To show this error the more apparently, let us apply it to the year 1715. In this year, then, the vernal equinox falls on the 10th of March; and therefore comes too early by 11 days. The paschal full moon falls on the 7th of April; and therefore too late, with regard to the cycle, by three days. Easter, therefore, which should have been on the 10th of April, was that year on the 17th. The error here lies only in the metemptosis, or postposition of the moon, through the defect of the lunar cycle. If the full moon had fallen on the 11th of March, Easter would have fallen on the 13th of March; and therefore the error arising from the anticipation of the equinox would have exceedingly augmented that arising from the postposition. These errors, in course of time, were so multiplied, that the calendar no longer exhibited any regular Easter. Pope Gregory XIII. therefore, by the advice of Aloysius Lilius, in 1582, threw 10 days out of the month of October, to restore the equinox to its place, viz. the 21st of March; and thus introduced the form of the Gregorian year, with such a provision as that the equinox should be constantly kept to the 21st of March. The new moons and full moons, by advice of the same Lilius, were not to be indicated by golden numbers,
Kalendar. numbers, but by epacts. The kalendar, however, was still retained in Britain without this correction: whence there was a difference of 11 days between our time and that of our neighbours. But by 24 Geo. II. c. 23. the Gregorian computation is established here, and accordingly took place in 1752.