The Roman calendar changed its form several times in the time between the foundation of Rome and the fall of the Roman Empire. The founding of Rome is reported by many legends which in recent times are beginning to be supplemented by more scientific reconstructions The Roman Empire was the post-Republican phase of the ancient Roman civilization, characterised by an autocratic form of government and large territorial This article generally discusses the early Roman or 'pre-Julian' calendars. The word Calendar consist of two words 1 Cal ( in Pashto means Year in Hindi and Persian is Sal- also means Year The calendar used after 46 BC is discussed under the Julian calendar. Year 46 BC was the last year of the pre-Julian calendar. This year had 445 days due to the errors that had accumulated in the pre-Julian calendar The Julian calendar, a reform of the Roman calendar, was introduced by Julius Caesar in 46 BC and came into force in 45 BC (709 Ab urbe condita

Painting of the Roman calendar about 60 BC, before the Julian reform. Observe (enlarged) that it contains the months Quintilis ("QVI") and Sextilis ("SEX"), and displays the intercalary month ("INTER") as the far righthand column. Also see Quintilus in 12-month Roman calendar. In the 10-month Roman calendar, Quintilis is after Junius, The following Sextilis was the original Latin name for the sixth month in the Roman calendar. Intercalation is the insertion of a leap day week or month into some calendar years to make the calendar follow the seasons or moon phases

History of the calendar

The original Roman calendar is believed to have been a lunar calendar, which may have been based on one of the Greek lunar calendars. This article is about the Vietnamese holiday For the 1968 military operation that began on that holiday see Tết Offensive. By the traditional Xhosa calendar, the year began in June and ended in May when Canopus, a large star visible in the Southern Hemisphere, signalled the The Zoroastrian calendar is a religious Calendar used by members of the Zoroastrian faith and it is an approximation of the (tropical Solar calendar. The Runic calendar is a Perpetual calendar based on the 19 year long Metonic cycle of the Moon Mesoamerican calendars are the calendrical systems devised and used by the Pre-Columbian cultures of Mesoamerica. In the Mesoamerican calendars, Calendar Round dates are composed by interlacing the dates of a 260-day period ( Tzolk'in in the Maya Calendar, Tonalpohualli The Julian calendar, a reform of the Roman calendar, was introduced by Julius Caesar in 46 BC and came into force in 45 BC (709 Ab urbe condita The Calendar of saints is a traditional Christian method of organizing a Liturgical year on the level of days by associating each day with one or more Saints The Eastern Orthodox liturgical calendar describes and dictates the rhythm of the life of the Eastern Orthodox Church. The liturgical year, also known as the Christian year, consists of the cycle of liturgical seasons in Christian churches which determines when The Darian Calendar is a proposed system of time-keeping designed to serve the needs of any possible future human settlers on the planet Mars. The Discordian or Erisian calendar is an alternative Calendar used by some adherents of Discordianism. A perpetual calendar is a Calendar which is good for a span of many years such as the Runic calendar. A wall calendar is a Calendar intended for placement on a wall Economic calendar is a type of Calendar that is intended to inform financiers and traders about the scheduled major economic numbers (like CPI, The word Calendar consist of two words 1 Cal ( in Pashto means Year in Hindi and Persian is Sal- also means Year The Hellenic calendar &mdashor more properly the Hellenic calendars, for there was no uniform calendar imposed upon all of Classical Greece &mdashbegan in most Greek As the time between new moons averages 29. 5 days, its months would have been either hollow (29 days) or full (30 days). Full months were considered powerful and therefore auspicious; hollow months were unlucky. Roman traditions claimed that the calendar was invented by Romulus, the founder of Rome about 753 BC. Romulus (c 771 BC– c 717 BC and Remus (c 771 BC–c 753 BC are the traditional founders of Rome, appearing in Roman mythology Events and trends 756 BC — Founding of Cyzicus. 755 BC — Ashur-nirari V succeeds Ashur-Dan III as king of Assyria

Unlike our dates, which are numbered sequentially from the beginning of the month, the Romans counted backwards from three fixed points - the Nones, the Ides, and the Kalends of the following month. This system originated in the practice of "calling" the new month when the crescent was first observed in the west after sunset. From the shape and orientation of the new moon the number of days remaining to the nones would be proclaimed. The earliest known version contained ten months, and started at the vernal equinox; however, the months by this time were no longer 'lunar':

• Martius (31 days)
• Aprilis (30 days)
• Maius (31 days)
• Iunius (30 days)
• Quintilis (31 days)
• Sextilis (30 days)
• September (30 days)
• October (31 days)
• November (30 days) and
• December (30 days)

The calendar year lasted 304 days and there were about 61 days of winter that did not fall within the calendar. The month is a unit of Time, used with Calendars which is approximately as long as some natural period related to the motion of the Moon; An equinox is the event of the Sun passing over the Earth's equator in its annual cycle A lunar calendar is a Calendar that is based on cycles of the Moon phase. Events in March American Red Cross Month Fire Prevention month ( The Philippines) Women's History Month ( United April holidays and events National Poetry Month - in United States National Sexual Assault Awareness Month - in United MAY ( also known as: Mei メイ 메이 is a Korean singer well known in South Korea for singing the song "Miracle" Junius was the Latin name for the fourth (later sixth month in the Roman calendar that was before Quintilis. Also see Quintilus in 12-month Roman calendar. In the 10-month Roman calendar, Quintilis is after Junius, The following Sextilis was the original Latin name for the sixth month in the Roman calendar. Events in September It is the start of the academic year in many countries in the Northern Hemisphere. October events and holidays Children's Book Week ( England) - First Week of October National Day ( China People's Republic Events in November All Saints' Day (formerly All Hallows Day a Christian holy day is celebrated on November 1, the day after Halloween Events in December Union Day of Romania (1 December World AIDS Day ( December 1) National Day of

Romans considered odd numbers to be lucky and even numbers unlucky. This superstition influenced the first reform of the calendar, which was attributed to Numa Pompilius, the second of the seven traditional Kings of Rome. A calendar reform is any significant revision of a Calendar system Numa Pompilius, according to Legend, was the second King of Rome, succeeding Romulus. The King of Rome ( Latin: rex regis) was the Chief magistrate of the Roman Kingdom. He is said to have added January and February to the end of the calendar around 713 BC. Events and trends Judah, Tyre and Sidon revolt against Assyria. Twelve lunar months, each averaging a little over 29. 53 days, come to 354. 37 days. To make his new months, Numa added 50 days to the year. He wanted each month and also the year to have an odd number of days, but since this was not possible he brought the length of the calendar year up to 355 days and took one day from each 30-day month, giving a total 57 days to share between January and February. February was made hollow with 28 days and all the other months were full:

• Martius (31 days)
• Aprilis (29 days)
• Maius (31 days)
• Iunius (29 days)
• Quintilis (31 days)
• Sextilis (29 days)
• September (29 days)
• October (31 days)
• November (29 days)
• December (29 days)
• Ianuarius (29 days)
• Februarius (28 days)

February was split into two parts, each with an odd number of days. The word " Ianuarius " is the original Roman designation of the month January Overview February was named after the Latin term februum, which means purification, via the purification ritual Februa held on February 15 in the The first part ended with the Terminalia on the 23rd; this was considered the end of the religious year. The five remaining days formed the second part.

The later months are named based on their position in the original calendar — September comes from septem meaning seven, October from octo meaning eight, November from novem meaning nine, December from decem meaning ten. These names have been retained even though September, October, November, and December are, respectively, the ninth, tenth, eleventh, and twelfth months of the modern calendar. Quintilis and Sextilis were later renamed July and August in honour of Julius Caesar and Augustus. Augustus ( Latin: IMPERATOR·CAESAR·DIVI·FILIVS·AVGVSTVS September 23 63 BC – August 19 AD 14) born Gaius Octavius Thurinus, was

The nones are related to the nundinae, the market days which fell on the eighth day of the eight-day market week used by the Romans. They are so called because in the Roman system of inclusive counting they came every nine days. From the nones to the ides there was exactly one market week. From the ides to the end of the month (except in February) there were exactly two market weeks. Hence the mnemonic

"March, May, July, October,

These are they,

Make nones the seventh,

Ides the fifteenth day. "

In all other months, nones were on the fifth and ides on the thirteenth. The preceding day was Pridie, e. g. Prid. Id. Mart. = 14 March. Other days were ante diem, ("days before"), e. g. a. d. III Kal. Oct. = 28 September. Note that the inclusive system of counting meant that the second day before the fixed point did not exist. Some other examples: a. d. IV Non. Jan. = 2 January; a. d. VI Non. Mai. = 2 May; a. d. VIII Id. Apr. = 6 April; a. d. VIII Id. Oct. = 8 Oct; a. d. XVII Kal. Nov. = 16 October; a. d. XVII Kal. Dec. = 14 November.

In order to keep the calendar year roughly aligned with the solar year, a leap month, the Mensis Intercalaris, sometimes also known as Mercedonius or Mercedinus, was added from time to time in between the two parts of February. Intercalation is the insertion of a leap day week or month into some calendar years to make the calendar follow the seasons or moon phases Mercedonius, also known as Intercalaris, was the Intercalary month added in Leap years of the Roman calendar. This caused the second part of February to be incorporated in the intercalary month as its last five days. There was thus no change either in their dates or the festivals observed on them. The resulting year was either 377 or 378 days long, depending on whether Intercalaris began on the day after the Terminalia^[1] or the second day after the Terminalia^[2]. Intercalaris had 27 days. Its nones were on the fifth and its ides on the thirteenth as usual; the next following day was a. d. XV Kal. Mart.

The decision to insert the intercalary month was the responsibility of the pontifex maximus. Intercalation is the insertion of a leap day week or month into some calendar years to make the calendar follow the seasons or moon phases The Pontifex Maximus was the high priest of the Ancient Roman College of Pontiffs. On average, this happened roughly in alternate years.

The system of aligning the year through intercalary months broke down at least twice. The first time was during and after the Second Punic War. It led to the reform of the Lex Acilia in 191 BC. Events By place Roman Republic The Romans under Manius Acilius Glabrio and Cato the Elder cut the Seleucid The details of this reform are unclear, but it appears to have successfully regulated intercalation for over a century. Intercalation is the insertion of a leap day week or month into some calendar years to make the calendar follow the seasons or moon phases The second breakdown was in the middle of the first century BC. This breakdown may have been related to the increasingly chaotic and adversarial nature of Roman politics at the time. The position of pontifex maximus was not a full-time job; it was held by a member of the Roman elite, who would almost invariably be involved in the machinations of Roman politics. Because a Roman calendar year defined the term of office of elected Roman magistrates, a pontifex maximus would have reason to lengthen a year in which he or his allies were in power, or not to lengthen a year in which his political opponents held office. The Roman Magistrates were elected officials in Ancient Rome. It was while Julius Caesar was pontifex maximus that the calendar was overhauled, with the result being the Julian calendar. The Julian calendar, a reform of the Roman calendar, was introduced by Julius Caesar in 46 BC and came into force in 45 BC (709 Ab urbe condita The calendar reforms were completed during the reign of his successor Augustus. Augustus ( Latin: IMPERATOR·CAESAR·DIVI·FILIVS·AVGVSTVS September 23 63 BC – August 19 AD 14) born Gaius Octavius Thurinus, was

Months

The three reference dates were probably declared publicly when the lunar conditions were observed. After the reforms of Numa Pompilius, they occurred on fixed days. Numa Pompilius, according to Legend, was the second King of Rome, succeeding Romulus.

• Kalendae (Kalends) — first day of the month, from which the word "calendar" is derived; thought to have originally been the day of the new moon. The word Calendar consist of two words 1 Cal ( in Pashto means Year in Hindi and Persian is Sal- also means Year Lunar phase (or Moon phase refers to the appearance of the illuminated portion of the Moon as seen by an observer usually on Earth Interest on debt was due on Kalends. Interest is a fee paid on borrowed capital Assets lent include Money, Shares, Consumer goods through Hire purchase, major assets Debt is that which is owed usually referencing Assets owed but the term can cover other obligations
• Nonae (Nones) — thought to have originally been the day of the half moon. Lunar phase (or Moon phase refers to the appearance of the illuminated portion of the Moon as seen by an observer usually on Earth
• Idūs (Ides) — thought to have originally been the day of the full moon. Lunar phase (or Moon phase refers to the appearance of the illuminated portion of the Moon as seen by an observer usually on Earth The Romans considered this an auspicious day in their calendar. The word ides comes from Latin, meaning "half division" (of a month). Latin ( lingua Latīna, laˈtiːna is an Italic language, historically spoken in Latium and Ancient Rome.

Some dates are sometimes known by the name of a festival that occurred on them, or shortly afterwards. Such dates are known for the Feralia, Quirinalia and the Terminalia (though not yet for the Lupercalia). Feralia was a Roman feast honoring the "infernal powers" In Roman mythology, Quirinus was an early god of the Roman state For the saint by the name 'Lupercus' see Marcellus of Tangier. These dates are all after the Ides of February, which suggests that they are connected with resolving an ambiguity that could arise in intercalary years: dates of the form a. d. [N] Kal. Mart. were dates in late February in regular years but were a month later in intercalary years. However, it is much debated whether there was a fixed rule for using festival-based dates. It has been suggested that dates like a. d. X Terminalia (known from an inscription in 94 B. C. ) indicated that the year was intercalary, that it was not intercalary, or that it could be intercalary.

When Julius Caesar added a day to September, he added it to the end of the month, so as not to disturb the dates of religious festivals in September, but the effect was to increase the count of the day that immediately followed the Ides:

a. d. XVIII Kal. Oct. = 18 days before the Kalends of October = 14 September

As a result, the position of all the following dates in September got bumped up by one day. Events 81 - Domitian becomes Emperor of the Roman Empire upon the death of his brother Titus. This has some unexpected effects. For example, the emperor Augustus was born on 23 September 63 BC. Augustus ( Latin: IMPERATOR·CAESAR·DIVI·FILIVS·AVGVSTVS September 23 63 BC – August 19 AD 14) born Gaius Octavius Thurinus, was Events 1122 - Concordat of Worms. 1459 - Battle of Blore Heath, the first major battle of the English Year 63 BC was a year of the pre-Julian calendar. Events By place Rome Pompey conquers Phonecia, Coele-Syria In the pre-Julian calendar this is 8 days before the Kalends of October (or, in Roman style, a. d. VIII Kal. Oct. ), but in the Julian calendar it is 9 days (a. d. IX Kal. Oct. ). Because of this ambiguity, his birthday was sometimes celebrated on both dates, i. e. (for us) on both 23 and 24 September. Events 622 - Prophet Muhammad completes his hegira from Mecca to Medina.

Nundinal cycle

The Roman Republic, like the Etruscans, used a "market week" of eight days, marked as A to H in the calendar. Etruscan civilization is the modern English name given to the culture and way of life of a people of ancient Italy The market cycle is known as the "nundinal cycle". Since the length of the year was not a multiple of 8 days, the letter for the market day (known as a "nundinal letter") changed every year. For example, if the letter for market days in some year was A and the year was 355 days long, then the letter for the next year would be F.

The nundinal cycle formed a basic rhythm of day-to-day Roman life; the market day was the day that country people would come to the city, and the day that city people would buy their groceries for the next 8 days. For this reason, a law was passed in 287 BC (the Lex Hortensia) that forbade the holding of meetings of the comitia (for example to hold elections) on market days, but permitted the holding of legal actions. Events By place Roman Republic A new law Lex Hortensia, gives much greater power to the Plebeian Assembly compared to the Senate In the late republic, a superstition arose that it was unlucky to start the year with a market day (i. e. for the market day to fall on 1 January, with a letter A), and the pontiffs, who regulated the calendar, took steps to avoid it. New Year See also New Year The Ancient Romans began their consular year on January 1st since 153 BC

Because the nundinal cycle was absolutely fixed at 8 days under the Republic, information about the dates of market days is one of the most important tools we have for working out the Julian equivalent of a Roman date in the pre-Julian calendar. In the early Empire, the Roman market day was occasionally changed. The details of this are not clear, but one likely explanation is that it would be moved by one day if it fell on the same day as the festival of Regifugium, an event that could occur every other Julian leap year. In the Roman religion, Regifugium or Fugalia was an annual observance that took place every February 24. When this happened the market day would be moved to the next day, which was the bissextile (leap) day.

The nundinal cycle was eventually replaced by the modern seven-day week, which first came into use in Italy during the early imperial period, after the Julian calendar had come into effect. A week (also called sennight or sevennight) is a unit of Time longer than a Day and shorter than a Month. The Julian calendar, a reform of the Roman calendar, was introduced by Julius Caesar in 46 BC and came into force in 45 BC (709 Ab urbe condita The system of nundinal letters was also adapted for the week, see dominical letter. Dominical letters are letters A B C D E F and G assigned to days in a cycle of seven with the letter A always set against 1 January as an aid for finding the day of the Week For a while, the week and the nundinal cycle coexisted, but by the time the week was officially adopted by Constantine in AD 321 the nundinal cycle had fallen out of use. Flavius Valerius Aurelius Constantinus (27 February ca. 272 &ndash 22 May 337 commonly known as Constantine I, Constantine the Great, or Saint Constantine Events By Topic Roman Empire March 7 — Edict of Constantine I: The dies Solis Invicti (Sunday is proclaimed as For further information on the week, see week and days of the week. A week (also called sennight or sevennight) is a unit of Time longer than a Day and shorter than a Month. The names of the days of the week in various world languages can be classified as either numerical or planetary; however in either case the names of one or more days

Character of the day

Each day of the Roman calendar was associated with a "character", which was marked in the fasti. Fasti, a Latin word refers to the Roman calendar and Almanac; and especially to a long possibly unfinished poem on the religious festivals The most important of these were dies fasti, marked by an F, on which legal matters could normally be heard, dies nefasti, marked by an N, on which they could not, and dies comitiales, marked by a C, on which meetings of the public assemblies known as comitia were permitted, subject to other constraints such as the Lex Hortensia. A few days had a different character, e. g. EN (endotercissus or perhaps endoitio exitio nefas), a day in which legal actions were permitted on half of the day only, and NP, which were public holidays.

Years

Fragment of an imperial-age consular fasti, Museo Epigrafico, Rome

In the Roman Republic, the years were not counted. The Roman Republic was the phase of the ancient Roman civilization characterized by a Republican form of government a period which began with the overthrow of the Instead they were named after the consuls who were in power at the beginning of the year (see List of Republican Roman Consuls). Consul (abbrev cos; Latin plural consules) was the highest elected office of the Roman Republic and an appointive office under the Empire This is a list of Roman consuls Key Abbreviations Imp = Imperator suff For example, 205 BC was The year of the consulship of Publius Cornelius Scipio Africanus and Publius Licinius Crassus. Events By place Seleucid Empire Returning via the Persian provinces of Arachosia, Drangiana, and Carmania Lists of consuls were maintained in the fasti. Fasti, a Latin word refers to the Roman calendar and Almanac; and especially to a long possibly unfinished poem on the religious festivals

However, in the later Republic, historians and scholars began to count years from the founding of the city of Rome. Different scholars used different dates for this event. The date most widely used today is that calculated by Varro, 753 BC, but other systems varied by up to several decades. Marcus Terentius Varro (116 BC &ndash 27 BC also known as Varro Reatinus to distinguish him from his younger contemporary Varro Atacinus, was a Roman Events and trends 756 BC — Founding of Cyzicus. 755 BC — Ashur-nirari V succeeds Ashur-Dan III as king of Assyria Dates given by this method are numbered ab urbe condita (meaning after the founding of the city, and abbreviated AUC). Ab Urbe condita (literally "from When reading ancient works using AUC dates, care must be taken to determine the epoch used by the author before translating the date into a Julian year.

The first day of the consular term, which was effectively the first day of the year, changed several times during Roman history. It became 1 January in 153 BC. New Year See also New Year The Ancient Romans began their consular year on January 1st since 153 BC Before then it was 15 March. Events 44 BC - Julius Caesar, Dictator of the Roman Republic, is stabbed to death by Marcus Junius Brutus, Earlier changes are a little less certain. There is good reason to believe it was 1 May for most of the third century BC, till 222 BC. Events 305 - Diocletian and Maximian retire from the office of Roman Emperor. Events By place Roman Republic Mediolanum (modern Milan) stronghold of the Gallic tribe of the Insubres Livy mentions consulates starting on 1 July before then, and arguments exist for other dates at earlier times. "July 1st" redirects here For the Ayumi Hamasaki song see H (song.

Converting pre-Julian dates

The fact that we use the same month names as the Romans encourages us to assume that a Roman date occurred on the same Julian date as its modern equivalent. This assumption is not correct. Even early Julian dates, before the leap year cycle was stabilised, are not quite what they appear to be. For example, it is well known that Julius Caesar was assassinated on the Ides of March in 44 BC, and this is usually converted to 15 March 44 BC. The Ides of March ( Latin: Idus Martiae is the name of the date 15 March in the Roman calendar. Year 44 BC was a Common year starting on Sunday (link will display the full calendar of the Julian calendar. Events 44 BC - Julius Caesar, Dictator of the Roman Republic, is stabbed to death by Marcus Junius Brutus, Year 44 BC was a Common year starting on Sunday (link will display the full calendar of the Julian calendar. While he was indeed assassinated on the 15th day of the Roman month Martius, the equivalent date on the modern Julian calendar is probably 14 March 44 BC. Events 1489 - The Queen of Cyprus, Catherine Cornaro, sells her kingdom to Venice. Year 44 BC was a Common year starting on Sunday (link will display the full calendar of the Julian calendar.

Finding the exact Julian equivalent of a pre-Julian date can be very hard. Since we have an essentially complete list of the consuls, it is not difficult to find the Julian year that generally corresponds to a pre-Julian year. However, our sources very rarely tell us which years were regular, which were intercalary, and how long an intercalary year was. Nevertheless, we do know that the pre-Julian calendar could be substantially out of alignment with the Julian calendar. Two precise astronomical synchronisms given by Livy show that in 168 BC the two calendars were misaligned by more than 2 months, and in 190 BC they were 4 months out of alignment. Events By place Greece The Battle of the Eurymedon is fought between a Seleucid fleet and ships from Rhodes and

We have a number of other clues to help us reconstruct the Julian equivalent of pre-Julian dates. First, we know the precise Julian date for the start of the Julian calendar (although there is some uncertainty even about that), and we have detailed sources for the previous decade or so, mostly in the letters and speeches of Cicero. Combining these with what we know about how the calendar worked, especially the nundinal cycle, we can accurately convert Roman dates after 58 BC relative to the start of the Julian calendar. Year 58 BC was a year of the pre-Julian calendar. Events By place Rome Consuls Lucius Calpurnius Piso Caesoninus Also, the histories of Livy give us exact Roman dates for two eclipses in 190 BC and 168 BC, and we have a few loose synchronisms to dates in other calendars which help to give rough (and sometimes exact) solutions for the intervening period. Titus Livius (traditionally 59 BC &ndash AD 17 known as Livy in English, was a Roman historian who wrote a monumental history of Rome Events By place Greece The Battle of the Eurymedon is fought between a Seleucid fleet and ships from Rhodes and Before 190 BC the alignment between the Roman and Julian years is determined by clues such as the dates of harvests mentioned in the sources. Events By place Greece The Battle of the Eurymedon is fought between a Seleucid fleet and ships from Rhodes and

Combining these sources of data, we are able to estimate approximate Julian equivalents of Roman dates back to the start of the First Punic War in 264 BC. The First Punic War ( 264 to 241 BC) was the first of three major wars fought between Carthage and the Roman Republic. Events By place Greece Abantidas, the son of Paseas, becomes Tyrant of the Greek city-state of Sicyon after However, while we have enough data to make such reconstructions, the number of years before 45 BC for which we can convert pre-Julian Roman dates to Julian dates with certainty is very small, and several reconstructions of the pre-Julian calendar are possible. Year 45 BC was the year the Julian calendar went into effect According to this calendar it was a Leap year starting on Friday (link will display the full calendar One detailed reconstruction giving conversions from pre-Julian dates into Julian dates is available at [1].

See also

• Ancient Rome

Notes

References and further reading

• Ovid - Fasti
• Plutarch - Numa Pompilius
• Bickerman, E. Publius Ovidius Naso ( March 20, 43 BC – 17 AD was a Roman poet known to the English -speaking world as Ovid who wrote on many topics including Lucius Mestrius Plutarchus ( Greek: Μέστριος Πλούταρχος c J. Chronology of the Ancient World. (London: Thames & Hudson, 1969, rev. ed. 1980).
• Brind'Amour, P. Le Calendrier romain: Recherches chronologiques (Ottawa, 1983)
• Feeney, Denis C. Caesar's Calendar: Ancient Times and the Beginnings of History. Berkeley: University of California Press, 2007 (hardcover, ISBN 0520251199).
• Michels, A. K. The Calendar of the Roman Republic (Princeton, 1967).
• Richards, E. G. Mapping Time. Oxford: Oxford University Press. ISBN 0-19-850413-6.

External links

• Bill Hollon's site
• Date Conversion for Julian and Gregorian dates
• Early Roman Calendar - History
• James Grout: The Roman Calendar, part of the Encyclopædia Romana
• Roman Dates (Chris Bennett's site)
• Smith's Dictionary article