Editing Mercedonius

{{Short description|Intercalary month of the Roman calendar}}
'''Mercedonius''' ([[Latin language|Latin]] for "Work Month"),<ref>{{citation |author=[[Plutarch]] |title=Life of Caesar |at=[https://www.perseus.tufts.edu/hopper/text?doc=urn:cts:greekLit:tlg0007.tlg048.perseus-eng1:59.2 lix, 2] }}.</ref><ref name=mom14>{{citation |last=Mommsen |first=Theodor |title=The History of Rome, ''Vol. I'' |url=http://www.gutenberg.org/cache/epub/10701/pg10701-images.html |editor-last=Dickson |editor-first=William Purdie |authorlink=Theodor Mommsen |date=1894 |at=Ch. xiv }}.</ref>{{efn|All Roman month names began as adjectives modifying the explicit or implicit word "month" ({{langx|la|mensis}}) before beginning to be treated as nouns in their own right. {{lang|la|Mercedonius}} seems to derive from {{lang|la|merces}}, meaning "wages".}} also known as '''Mercedinus''',<ref>{{citation |author=[[Plutarch]] |title=Life of Numa |at=[https://www.perseus.tufts.edu/hopper/text?doc=urn:cts:greekLit:tlg0007.tlg005.perseus-eng1:18.2 xviii, 2] }}.</ref> '''Interkalaris'''<ref>''[[Fasti Triumphales]]''.</ref> or '''Intercalaris''' ({{langx|la|mensis intercalaris}}), was the [[intercalary month]] of the [[Roman calendar]]. The resulting [[leap year]] was either 377 or 378 days long. It theoretically occurred every two (or occasionally three) years, but was sometimes avoided or employed by the [[college of Pontiffs|Roman pontiffs]] for political reasons regardless of the state of the solar year. Mercedonius was eliminated by [[Julius Caesar]] when he introduced the [[Julian calendar]] in 45 BC.

==History==
This month, instituted according to Roman tradition by [[Numa Pompilius]],<ref name=Liddell-1909>{{cite book |first=H.G. |last=Liddell |author-link=Henry Liddell |year=1909 |title=A History of Rome |publisher=John Murray |place=London, UK |page=29}}</ref> was supposed to be inserted every two or three years to align the conventional 355-day Roman year with the [[tropical year|solar year]].{{efn|
[[Livy]]: "The lunar year of 354&nbsp;days fell short of the solar year by {{sfrac|11|1|4}}&nbsp;days: In 8&nbsp;years this amounted to 90&nbsp;days or three months. These 90&nbsp;days he divided into two months of 22&nbsp;and two months of 23&nbsp;days, and introduced them alternately every second year for two octennial periods: every third octennial period, however, Numa intercalated only ... three months ... because he adopted 355&nbsp;days as the length of his lunar year".<ref name=Livy-Spillan>{{cite book |author=[[Livy]] |title=History of Rome |at=Book&nbsp;I, 19, footnote&nbsp;24 |translator=Spillan, Daniel |url=http://www.gutenberg.org/files/19725/19725-0.txt |via=gutenberg.org}} See also: {{lang|la|[[Ab urbe condita (Livy)|Ab urbe condita]]}} ("Since the founding of the city" / ''History of Rome'').</ref>
:
The same theory is proposed by [[Macrobius]].<ref>{{cite book |author=[[Macrobius]] |date=c. 430 |title=Saturnalia |title-link=Saturnalia (Macrobius)}}</ref>
:
[[Plutarch]] wrote: "Numa reckoned the variation to consist of eleven days, as the lunar year contains 354 days, and the solar year 365. He doubled those eleven days and introduced them every other year, after February, as an intercalary month, twenty-two days in duration, which was called by the Romans Mercedinus."<ref>{{cite book |author=[[Plutarch]] |title=Parallel Lives }}, ''Numa'' section XVIII</ref>
}}

The decision of whether to insert the intercalary month was made by the [[pontifex maximus]], supposedly based on observations to ensure the best possible correspondence with the [[season]]s.{{efn|
"Their {{grey|[intercalary months']}} management was left to the pontiffs – {{lang|la|ad metam eandem solis unde orsi essent-dies congruerent}} ("that the days might correspond to the same starting-point of the sun in the heavens whence they had set out").<ref name=Livy-Spillan/>
}}
However, the pontifex maximus would normally be an active politician, and the decision would often be manipulated to allow friends to stay in office longer or force enemies out early.<ref>[[Censorinus]], ''[[De Die Natali|On the Natal Day]]'', Ch. XX.</ref>  Such unpredictable intercalation meant that dates following the month of Februarius could not be known in advance, and further to this, Roman citizens living outside Rome would often not know the current date.

The exact mechanism is not clearly specified in ancient sources. Some scholars{{refn|
such as [[Christian Ludwig Ideler|L.C. Ideler]],<ref>{{cite book |first=C. Ludwig |last=Ideler |author-link=Christian Ludwig Ideler |year=1825 |title=Handbuch der mathematischen und technische Chronologie |lang=de |trans-title=Handbook of Mathematical and Technical Chronology |place=Berlin, DE}}</ref> [[Henry Liddell|H.G. Liddell]],<ref name=Liddell-1909/> [[Elias Joseph Bickerman|E.J. Bickerman]],<ref>{{cite book |last=Bickerman |first=E.J. |author-link=Elias Joseph Bickerman |year=1980 |title=Chronology of the Ancient World |place=Ithaca, NY |publisher=Cornell U.P. |ISBN=0-80-141282-X}}</ref> and the staff writers of ''Encyclopædia Britannica''.{{cn|date=May 2023}}
}}
hold that in intercalary years February's length was fixed at 23&nbsp;days and it was followed by a variable-length {{lang|la|mensis intercalaris}} with 27 or 28&nbsp;days. This view is followed in generalist surveys of calendrical history.<ref>such as those of D.E. Duncan, G.R. Richards, or A. Aveni.{{full citation|date=May 2023|reason=each author needs a separate citation}}</ref>

However, following a discussion of intercalation by Michels (1967)<ref>{{cite book |author=Michels, A.K. |year=1967 |title=The Calendar of the Roman Republic |publisher=Princeton |pages=145–172}} — the standard reference on the pre-Julian calendar</ref> some specialist studies of the pre-Julian calendar published since 1967<ref>including papers and books by  A. E. Samuel, P. S. Derow, P. Brind'Amour, V.M. Warrior, J. Rüpke, R. Hannah, and C.J. Bennett{{full citation|date=May 2023|reason=each author needs a separate citation}}</ref> claim that in intercalary years Februarius was set at either 23 or 24&nbsp;days, which was followed by an intercalary month of 27&nbsp;days.

Whichever interpretation is correct, the days {{lang|la|a.d. VI Kal. Mart.}} to {{lang|la|Prid. Kal. Mart.}}, normally referring to the end of February, were in intercalary years the concluding days of the {{lang|la|mensis intercalaris}}.

The month was eliminated by Julius Caesar with his [[Julian calendar|revised calendar]] in 45 BC.

==See also==
*[[Roman Calendar]] and [[Julian calendar#Motivation|Julian calendar § Motivation]]
*[[Adar]]
*[[Undecimber]]

==Notes==
{{noteslist}}

==References==
{{reflist|30em}}

==External links==
*[https://web.archive.org/web/20050405040546/http://www.tyndale.cam.ac.uk/Egypt/ptolemies/chron/roman/chron_rom_cal.htm Roman Dates]
{{Roman months}}
[[Category:Months]]
[[Category:Months of the Roman calendar]]