Roman calendar From Wikipedia, the free encyclopedia The Roman calendar is the calendar used by the Roman kingdom and republic. It is often inclusive of the Julian calendar established by the reforms of the dictator Julius Caesar and emperor Augustus in the late 1st century BC and sometimes inclusive of any system dated by inclusive counting towards months' kalends, nones, and ides in the Roman manner. It is usually exclusive of the Alexandrian calendar of Roman Egypt, which continued the unique months of that land's former calendar; the Byzantine calendar of the later Roman Empire, which usually dated A reproduction of the fragmentaryFasti Antiates the Roman months in the simple count of the ancient Greek Maiores (c. 60 BC), with the seventh and eighth months calendars; and the Gregorian calendar, which refined the still named Quintilis ("QVI") and Sextilis ("SEX") and Julian system to bring it into still closer alignment with the an intercalary month ("INTER") in the far righthand solar year and is the basis of the current international column standard. Roman dates were counted inclusively forward to the next of three principal days: the first of the month (the kalends), a day less than the middle of the month (the ides), and eight days—nine, counting inclusively—before this (the nones). The original calendar consisted of 10 months beginning in spring with March; winter was left as an unassigned span of days. These months ran for 38 nundinal cycles, each forming a kind of eight (i.e., "nine") day week ended by religious rituals and a public market. The winter period was then used to create January and February. The legendary early kings Romulus and Numa were traditionally credited with establishing this early fixed calendar, which bears Another reproduction of theFasti Antiates Maiores traces of its origin as an observational lunar one. In particular, the kalends, nones, and ides seem to have derived from the first sighting of the crescent moon, the first-quarter moon, and the full moon respectively. The system ran well short of the solar year, and it needed constant intercalation to keep religious festivals and other activities in their proper seasons. For superstitious reasons, such intercalation occurred within the month of February even after it was no longer considered the last month. After the establishment of the Roman Republic, years began to be dated by consulships and control over intercalation was granted to the pontifices, who eventually abused their power by lengthening years controlled by their political allies and shortening the years in their rivals' terms of office. Having won his war with Pompey, Caesar used his position as Rome's chief pontiff to enact a calendar reform in 46 BC, coincidentally making the year of his third consulship last for 446 days. In order to avoid interfering with Rome's religious ceremonies, the reform added all its days towards the ends of months and did not adjust any nones or ides, even in months which came to have 31 days. The Julian calendar was supposed to have a single leap day on 24 February (a doubled VI Kal. Mart.) every fourth year but following Caesar's assassination the priests figured this using inclusive counting and mistakenly added the bissextile day every three years. In order to bring the calendar back to its proper place, Augustus was obliged to suspend intercalation for a few decades. The revised calendar remaining slightly longer than the solar year, the date of Easter shifted far enough away from the vernal equinox that Pope Gregory XIII ordered its adjustment in the 16th century. Contents 1 History 1.1 Prehistoric lunar calendar 1.2 Legendary 10-month calendar 1.3 Republican calendar 1.4 Flavian reform 1.5 Julian reform 1.6 Later reforms 2 Days 3 Weeks 4 Months 5 Intercalation 6 Years 7 Conversion to Julian or Gregorian dates 8 See also 9 Notes 10 References 10.1 Citations 10.2 Bibliography 11 External links History Prehistoric lunar calendar The original Roman calendar is believed to have been an observational lunar calendar[1] whose months began from the first signs of a new 1 crescent moon. Because a lunar cycle is about 29 ⁄2 days long, such months would have varied between 29 and 30 days. Twelve such months would have fallen 10 or 11 days short of the solar year; without adjustment, such a year would have quickly rotated out of alignment with the seasons in the manner of the present-day Islamic calendar. Given the seasonal aspects of the later calendar and its associated religious festivals, this was presumably avoided through some form of intercalation or through the suspension of the calendar during winter. The remains of the Fasti Praenestini Rome's 8-day week, the nundinal cycle, was shared with the Etruscans, who used it as the schedule of royal audiences. It was presumably a feature of the early calendar and was credited in Roman legend variously to Romulus and Servius Tullius. Legendary 10-month calendar The Romans themselves described their first organized year as one with ten fixed months, each of 30 or 31 days.[2][3] Such a decimal division fit general Roman practice.[4] The four 31-day months were called "full" (pleni) and the others "hollow" (cavi).[a][6] Its 304 days made up exactly 38 nundinal cycles. The system is usually said to have left the remaining 50-odd days of the year as an unorganized "winter", although Licinius Macer's lost history apparently stated the earliest Roman calendar employed intercalation instead[7][8] and Macrobius claims the 10-month calendar was allowed to shift until the summer and winter months were completely misplaced, at which time additional days belonging to no month were simply inserted into the calendar until it seemed things were restored to their proper place.[9][10] Later Roman writers credited this calendar to Romulus,[11][12] their legendary first king and culture hero, although this was common with other practices and traditions whose origin had been lost to them. Some scholars doubt the existence of this calendar at all, as it is only attested in late Republican and Imperial sources and apparently supported only by the misplaced names of the months from September to December.[13] Rüpke and apparently supported only by the misplaced names of the months from September to December.[13] Rüpke also finds the coincidence of the length of the supposed "Romulan" year with the length of the first ten months of the Julian calendar to be suspicious.[13] "Calendar of Romulus" Length English Latin Meaning in days [2][3] March Mensis Martius Month of Mars 31 April Mensis Aprilis Uncertain 30 May Mensis Maius Uncertain 31 June Mensis Iunius Month of Juno 30 Mensis Quintilis Quintilis Fifth Month 31 Mensis Quinctilis[14] Sextilis Mensis Sextilis Sixth Month 30 September Mensis September Seventh Month 30 October Mensis October Eighth Month 31 November Mensis November Ninth Month 30 December Mensis December Tenth Month 30 — (51) Other traditions existed alongside this one, however. Plutarch's Parallel Lives recounts that Romulus's calendar had been solar but adhered to the general principle that the year should last for 360 days. Months were employed secondarily and haphazardly, with some counted as 20 days and others as 35 or more.[15][16] Republican calendar The attested calendar of the Roman Republic was quite different. It followed Greek calendars in assuming a 1 1 3 lunar cycle of 29 ⁄2 days and a solar year of 12 ⁄2 synodic months ( 368 ⁄4 days), which align every fourth year after the addition of two intercalary months.[6] The additional two months of the year were January and February; the intercalary month was sometimes known as Mercedonius.[6] The Romans did not follow the usual Greek practice in alternating 29- and 30-day months and a 29- or 30-day intercalary month every other year. Instead, their 3rd, 5th, 7th, and 10th months[b] had 31 days each; all the other months had 29 days except February, which had 28 days for three years and then 29 every fourth year. The total of these months over a 4-year span differed from the Greeks by 5 days, meaning the Roman intercalary month always had 27 days. Similarly, within each month, the weeks did not vary in the Greek fashion between 7 and 8 days; instead, the full months had two additional days in their first week and the other three weeks of every month ran for 8 days ("nine" by Roman reckoning).[17] Still more unusually, the intercalary month was not placed at the end of the year but within the month of February after the Terminalia on the 23rd (a.d. VII Kal. Mart.); the remaining days of February followed its completion. This seems to have arisen from Roman superstitions concerning the numbering and order of the months. The arrangement of the Roman calendar similarly seems to have arisen from Pythagorean superstitions concerning the luckiness of odd numbers.[17] These Pythagorean-based changes to the Roman calendar were generally credited by the Romans to Numa Pompilius, Romulus's successor and the second of Rome's seven kings, as were the two new months of the calendar.[18][19][c] Most sources thought he had established intercalation with the rest of his calendar. Although Livy's Numa instituted a lunar calendar, the author claimed the king had instituted a 19-year system of intercalation equivalent to the Metonic Cycle[20] centuries before its development by Babylonian and Greek intercalation equivalent to the Metonic Cycle[20] centuries before its development by Babylonian and Greek astronomers.[d] Plutarch's account claims he ended the former chaos of the calendar by employing 12 months totaling 354 days—the length of the lunar and Greek years—and biennial intercalary months of 22 days.[15][16] Plutarch believed Numa was responsible for placing January and February first in the calendar;[15][16] Ovid states January began as the first month and February the last, with its present order owing to the Decemvirs.[22][23] W.