Talk:Babylonian calendar

From Wikipedia, the free encyclopedia
Jump to: navigation, search
          This article is of interest to the following WikiProjects:
WikiProject Iraq (Rated Start-class, Top-importance)
WikiProject icon This article is within the scope of WikiProject Iraq, a collaborative effort to improve the coverage of Iraq on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.
Start-Class article Start  This article has been rated as Start-Class on the project's quality scale.
 Top  This article has been rated as Top-importance on the project's importance scale.
 
WikiProject Time (Rated Start-class, Low-importance)
WikiProject icon This article is within the scope of WikiProject Time, a collaborative effort to improve the coverage of Time on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.
Start-Class article Start  This article has been rated as Start-Class on the project's quality scale.
 Low  This article has been rated as Low-importance on the project's importance scale.
 
WikiProject Ancient Near East (Rated Start-class, High-importance)
WikiProject icon This article is within the scope of WikiProject Ancient Near East, a collaborative effort to improve the coverage of Ancient Near East related articles on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.
Start-Class article Start  This article has been rated as Start-Class on the project's quality scale.
 High  This article has been rated as High-importance on the project's importance scale.
 

WikiProject Time assessment rating comment[edit]

Want to help write or improve articles about Time? Join WikiProject Time or visit the Time Portal for a list of articles that need improving.
Yamara 17:12, 14 February 2008 (UTC)

Sources[edit]

[1] [2]

  • Sayce, Archibald Henry, “The Assyrian Calendar”, in: A.H. Sayce (ed.), Records of the Past, Being English Translations of the Ancient Monuments of Egypt and Western Asia (Samuel Bagster & Sons Ltd., London, 1875), vol. 1, pp. 166-167 [BrainFly link].
  • Jensen, Peter Christian Albrecht, “Zu den Ideogrammen der assyrischen Monatsnamen”, Zeitschrift für Assyriologie und verwandte Gebiete, 2 (1887), 209-211.
  • Meißner, Bruno, “[Babylonian Month Names]”, Wiener Zeitschrift für die Kunde des Morgenlandes, 5 (1891), 180-??? (*).
  • Mahler, Eduard, “[Babylonian Calendar]”, Zeitschrift für Assyriologie und verwandte Gebiete, 6 (1891), 457-??? – on the 19-year intercalation rule.
  • Mahler, Eduard, “Die Kalender der Babylonier”, Sitzungsberichte der Mathematisch-Naturwissenschaftliche Classe der Kaiserlichen Akademie der Wissenschaften zu Wien, 101 (1892), Abtheilung IIa, 337-353 – on the 19-year intercalation rule.
  • Mahler, Eduard, “Die Kalender der Babylonier (II. Mittheilung)”, Sitzungsberichte der Mathematisch-Naturwissenschaftliche Classe der Kaiserlichen Akademie der Wissenschaften zu Wien, 101 (1892), Abtheilung IIa, 1685-1693.
  • Mahler, Eduard, “Das Kalenderwesen der Babylonier”, in: E.D. Morgan (ed.), Transactions of the Ninth International Congress of Orientalists (Held in London, 5th to 12th September 1892) (Ballantyne Press, Edinburgh, 1893), vol. 2, pp. 209-217.
  • Jensen, Peter Christian Albrecht, “Geschichte der Namen der Wochentage: I. Die 7-tägige Woche in Babylon und Niniveh”, Zeitschrift für deutsche Wortforschung, 1 (1900), 150-160 (*).
  • Johns, Claude Hermann Walter, “On the Length of the Month in Babylonia”, Proceedings of the Society of Biblical Archaeology, 30 (1908), 221-230.
  • Mahler, Eduard, “Der Kalender der Babylonier”, in: Hilprecht Anniversary Volume: Studies in Assyriology and Archaeology dedicated to Hermann V. Hilprecht upon the Twenty-Fifth Anniversary of his Doctorate and his Fiftieth Birthday (July 28) by his Colleagues, Friends and Admirers (J.C. Hinrichs’she Buchhandlung/Luzac & Co./Librairie Paul Geuthner/The Open Court Publishing Co., Leipzig/London/Paris/Chicago, 1909), pp. 1-13.
  • Weissbach, Franz Heinrich, “Zum babyloninischen Kalender”, in: Hilprecht Anniversary Volume: Studies in Assyriology and Archaeology dedicated to Hermann V. Hilprecht upon the Twenty-Fifth Anniversary of his Doctorate and his Fiftieth Birthday (July 28) by his Colleagues, Friends and Admirers (J.C. Hinrichs’she Buchhandlung/Luzac & Co./Librairie Paul Geuthner/The Open Court Publishing Co., Leipzig/London/Paris/Chicago, 1909), pp. 281-290.
  • Ungnad, Arthur, “Zur Schaltungs-Praxis in der Hammurapi-Zeit”, Orientalistische Literaturzeitung, 13 (1910), 66-67 (*).* Weidner, Ernst Friedrich, “Studien zum Kalender der Hethiter und Babylonier”, Babyloniaca: Études de philologie assyro-babylonienne, 6 (1912), 164-181 [UMDL link] [erratum, ibid., 235 [UMDL link]].* Langdon, Stephen Herbert, “Astronomy and the Early Sumerian Calendar”, Proceedings of the Society of Biblical Archaeology, 34 (1912), 248-256.
  • Pinches, Theophilus Goldridge, “The Babylonian Month-Names of the Fifth Series”, Proceedings of the Society of Biblical Archaeology, 34 (1912), 292-295.
  • Barton, George Aaron, “Kugler’s Criterion for Determining the Order of the Months in the Earliest Babylonian Calendar”, Journal of the American Oriental Society, 33 (1913), 297-305 [JSTOR link].
  • Pinches, Theophilus Goldridge, “Notes upon the Early Sumerian Month-Names”, Proceedings of the Society of Biblical Archaeology, 35 (1913), 123-128.
  • Weidner, Ernst Friedrich, “Die Schaltungs-Praxis im alten Babylonien”, Memnon, 6 (1913), 65-75 (*).
  • Reidel, Wilhelm, “Die altbabylonischen Monatsnamen”, Zeitschrift für Assyriologie und verwandte Gebiete, 28 (1914), 294-302.
  • Schoch, Carl, “Die Dattelernte in Alt-Babylon und die Fixierung der Monatsanfangs und dem Neulicht”, Zeitschrift für Assyriologie und verwandte Gebiete, 37 (1926), 138-139 (*).
  • Weidner, Ernst Friedrich, “Der altassyrische Kalendar”, Archiv für Orientforschung, 5 (1928/29), 184-185.
  • Schoch, Carl, “Die Schaltjahre von Bursin I bis Ibisin I in Umma”, Zeitschrift für Assyriologie und verwandte Gebiete, 39 [= NF, 5] (1929), 226-228 (*).
  • Langdon, Stephen Herbert, “The Sumerian Word for “Year” and Origin of the Custom of Dating by Events”, Revue d’assyriologie et d’archéologie orientale, 32 (1935), 131-149.
  • van der Waerden, Bartel Leendert, “Plaudereien zur babylonischen Astronomie: II. Der Kalender von Nippur und die Zwölfmal drei Sterne”, Die Himmelswelt, ?? (1944), Heft 7/9, 1-4 (*).
  • Landsberger, Benno, “Jahreszeiten im Sumerisch-Akkadischen”, Journal of Near Eastern Studies, 8 (1949), 248-272 [JSTOR link] & 273-297 [JSTOR link].
  • Sachs, Abraham Joseph, “Sirius Dates in Babylonian Astronomical Texts of the Seleucid Period”, Journal of Cuneiform Studies, 6 (1952), 105-114 [JSTOR link].
  • Smith, Sidney, “Babylonian Time Reckoning”, Iraq, 31 (1969), 74-81 (*).
  • Kupper, J.R., “Le calendrier de Mari”, in: M.A. Beek, A.A. Kampman, C. Nijland & J. Ryckmans (eds.), Symbolae Biblicae et Mesopotamicae Francisco Mario Theodoro de Liagre Böhl dedicatae (E.J. Brill, Leiden, 1973 [= Nederlands Instituut voor het Nabije Oosten: Studia Francisci Scholten Memoriae Dicata, nr. 4]), pp. 266-270.
  • Hunger, Hermann & Reiner, Erica, “A Scheme for Intercalary Months from Babylonia”, Wiener Zeitschrift für die Kunde des Morgenlandes, 67 (1975), 21-28 (*).
  • Gomi, Tohru, “The Calendars of Ur and Puzri-Dagan in the Early Ur-III Period”, ASJ, 1 (1979), 1-11 (*).
  • Fales, Frederick Mario, “A List of Umma Month Names”, Revue d’assyriologie et d’archéologie orientale, 76 (1982), 70-71.
  • Donbaz, Veysel, “New Evidence on the Reading of the Old Assyrian Month-Name Kanwarta, with an Edition of the Memorandum kt c/k 839”, Jaarbericht van het Vooaziatisch-Egyptisch Genootschap Ex Oriente Lux, 28 (1983/84), 3-9.
  • Papke, Werner, “Zwei Plejaden-Schaltregeln aus dem 3. Jahrtausend”, Archiv für Orientforschung, 31 (1984, 67-70 – followed by “Remarks on the Article «Zwei Plejaden-Schaltregeln»” by D.E. Pingree on pp. 70-71.
  • Gomi, Tohru, “On the Position of the Month iti-ezem-dAmar-dSin in the Neo-Sumerian Umma Calendar”, Zeitschrift für Assyriologie und Vorderasiatische Archäologie, 75 (1985), 4-6.
  • Cooper, Marc, “The Drehem Calendars During the Reign of Šulgi”, Zeitschrift für Assyriologie und Vorderasiatische Archäologie, 77 (1987), 174-191.
  • Greengus, Samuel, “The Akkadian Calendar at Sippar”, Journal of the American Oriental Society, 107 (1987), 209-229 [JSTOR link].
  • Englund, Robert K., “Administrative Timekeeping in Ancient Mesopotamia”, Journal of the Economic and Social History of the Orient, 31 (1988), 121-185 [Periodicals Archive Online link].
  • Pomponio, Francesco, “The Reichskalender of Ur III in the Umma Texts”, Zeitschrift für Assyriologie und Vorderasiastische Archäologie, 79 (1989), 10-13.
  • Chadwick, Robert, “Calendars, Ziggurats, and the Stars”, Bulletin of the Canadian Society for Mesopotamian Studies, 24 (1992), 7-24 (*).
  • Veenhof, Klaas R., “The Old Assyrian hamuštum-Period: A Seven-Day Week”, Jaarbericht van het Vooaziatisch-Egyptisch Genootschap Ex Oriente Lux, 34 (1995/96), 5-26.
  • Bonechi, Marco, “On the III and II Millennium Month Names from *qsy, «to be cold»”, Nouvelles Assyriologiques Brèves et Utilitaires (N.A.B.U.) (1996), nr. 93 [p. 81].
  • Koch, Johannes, “AO 6478, MUL.APIN und das 364 Tage-Jahr”, Nouvelles Assyriologiques Brèves et Utilitaires (N.A.B.U.) (1996), nr. 111 [pp. 97-99].
  • Horowitz, Wayne, “The 360 and 364 Day Year in Ancient Mesopotamia”, The Journal of the Ancient Near Eastern Society, 24 (1997), 35-44.
  • Koch, Johannes, “Kannte man in Mesopotamien das 364 Tage-Jahr wirklich seit dem 7. Jahrhundert v.Chr.?”, Nouvelles Assyriologiques Brèves et Utilitaires (N.A.B.U.) (1997), nr. 119 [pp. 109-112]
  • Horowitz, Wayne, “The 364-Day in Mesopotamia, Again”, Nouvelles Assyriologiques Brèves et Utilitaires (N.A.B.U.) (1998), nr. 49 [pp. 49-51]
  • Koch, Johannes, “Ein für allemal: Das antike Mesopotamien kannte kein 364 Tage-Jahr”, Nouvelles Assyriologiques Brèves et Utilitaires (N.A.B.U.) (1998), nr. 121 [pp. 112-114]
  • Sayce, Archibald Henry, “The Chaldean Origin of the Sabbath”, The Academy: A Weekly Review of Literature, Science and Art, 8 (1875), 554-555 [nr. ???] [Periodicals Archive Online link].
  • Sayce, Archibald Henry, “A Babylonian Saints’ Calendar”, in: A.H. Sayce (ed.), Records of the Past, Being English Translations of the Ancient Monuments of Egypt and Western Asia (Samuel Bagster & Sons Ltd., London, 1876), vol. 7, pp. 157-170 [BrainFly link] – on the days of the intercalary month of Ulûlu.
  • Boscawen, William Saint Chad, “A Babylonian Calendar”, The Academy: A Weekly Review of Literature, Science and Art, 12 (1877), 472-473 [nr. ???] [Periodicals Archive Online link].
  • Bezold, Carl, “Eine assyrische “Hemerologie””, Zeitschrift für Assyriologie und verwandte Gebiete, 3 (1888), 243-248.
  • Boscawen, William Saint Chad, “The Babylonian and Jewish Festivals”, The Babylonian & Oriental Record: A Monthly Magazine of the Antiquities of the East, 4 (1889/90), 34-38 (*).
  • Jensen, Peter Christian Albrecht, “The Supposed Babylonian Origin of the Week and the Sabbath”, Sunday School Times (1892), nr. 3 (*).
  • Kohut, Alexander, “The Talmudic Records of Persian and Babylonian Festivals Critically Illustrated”, The American Journal of Semitic Languages and Literatures, 14 (1898), 183-194 [JSTOR link] – cf. also Revue des études juives, 24 (18??), 256-271 (*).
  • von Soden, Wolfram, “Gibt es ein Zeugnis dafür, daß die Babylonier an die Wiederauferstehung Marduks geglaubt haben?”, Zeitschrift für Assyriologie und Vorderasiatische Archäologie, 51 [= Neue Folge, 17] (1955), 130-166.
  • Berger, P.-R., “Das Neujahrsfest nach den Königsinschriften des ausgehenden babylonischen Reiches”, in: A. Finet (ed.), Actes de la XVIIe Rencontre Assyriologique Internationale, Université Libre de Bruxelles, 30 juin – 4 juillet 1969 (Comité belge de recherches en Mésopotamie, Ham-sur-Heure, 1970 [= Publications du Comité belge de recherches historiques, épigraphiques et archéologiques en Mésopotamie, nr. 1]), pp. 155-159.
  • Black, J.A., “The New Year Ceremonies in Ancient Babylon: “Taking Bel by the Hand” and a Cultic Picnic”, Religion, 11 (1981), 39-59 [??? link].

Lunar?[edit]

Was the Babylonian calendar really fully lunar until the 5th century BC? If so, why would regnal years of kings line up more or less with Julian year calculations of eclipse data? john k 20:09, 26 September 2005 (UTC)

Thanks! Somehow that escaped my notice. As far as I know, the Babylonian calendar was always lunisolar, thus it did not drift through the seasons like the present Islamic calendar does. But before about 499 BC it was purely observational, with the intercalary month being inserted only as needed. I'm changing the article. — Joe Kress 20:53, 26 September 2005 (UTC)

Vernal equinox[edit]

[Joe], your assumption that Babylonians had always used the 19-year cycle is false. The cycle was introduced probably in the V century BC. So do you imply that before that time there was no Babylonian calendar? Of course, there was, and Babylonians had to rely solely on the vernal equinox as a point of reference to fix the beginning of the new year in their calendar. This can be seen from the VI BC tablets. —The preceding unsigned comment was added by Bravehearted (talkcontribs) 12:33, 20 January 2007 (UTC).

I am well aware that the 19-year cycle only began in 499 BC, with only three minor exceptions until 380 BCE (thereafter there were no exceptions) according to the tables of Parker and Dubberstein (1956). But according to those same tables the earlier Babylonian calendar could not have used any astronomical cues (either the vernal equinox or the heliacal rising of a single star like Sirius) because there was too much variablility between intercalary months. There was simply no rhyme or reason to the years having an intercalary month before 500 BCE. If they had used an astronomical cue, then they would have introduced an intercalary month every two or three years, but there was a far greater variability in its frequency, so they must have been much more arbitrary in their decision on when to decree it. One possibility is that they used the heliacal risings of many stars, such as those listed in the MUL.APIN tablets, which allowed the astronomers to pick and chose which heliacal rising to accept or reject, allowing them or the king to aribitrarily decree that almost any year was or was not intercalary. Another possibility is that they may have used environmental clues, as did the later Hebrew calendar prior to the destruction of the Second Temple. Of course, the king could have ignored his astronomers and arbitrarily decreed the intercalary month as he saw fit. A final possibility is that the tables of Parker and Dubberstein are grossly in error, which I reject because those same tables are relied upon as evidence for the use of the 19-year cycle during the last half of the first millennium BCE. Of course, those tables no doubt have a few errors because other cuneiform tablets have been discovered, recognized, or re-interpreted since 1956 (see Sources for Babylonian to Julian Conversion), but their tables cannot have had gross errors. — Joe Kress 03:35, 21 January 2007 (UTC)
OK. Let's settle a couple of facts. First of all, on the basis of the Old Testament we can assume that Hebrews had begun their new calendar year sometime about the vernal equinox, because about the time of the Passover they had to present first freshly harvested barley grains. Also their first month had been called Abib relating to the greenish color of nearly ripe barley. So Jews without using any special system just relied on the looks of barley and also the weather conditions - rain season should have been over and roads fairly dry for the people to come to Jerusalem from all over Israel. But Babylonians who had no Passover also started their new year about the time of the vernal equinox even before the V c BC. This can be clearly shown from the dates of king Nebuchadnesar's reign. If Babylonians did not rely on the spring equinox, then what did they depend on in deciding on the time when their new calendar year should begin? Jews had nearly ripe barley and fairly dry roads, what data did Babylonians have? Because they must have relied on something as they never started their year before the vernal equinox, but alwas in the month starting on or after that day (again, data from Nebuchadnesar's reign). Bravehearted 17:08, 21 January 2007 (UTC)
The vernal equinox is never mentioned in the Torah. Instead, the first month or Abib had to be a spring month. "Spring" is a three month season which gives the first month great variability in time without violating Jewish law, similar to the variability of the meteorological cues that you mention (the condition of roads and the barley crop). The Babylonians were unaware of precession, that is, they made no distinction between a tropical year event like the vernal equinox and a sidereal year event like the heliacal rising of stars. Indeed, the Babylonian Mul.Apin tablets (1100–700 BC) specifically state that the constellation Perseus became visible on 1 Nisanu [3] without mentioning the vernal equinox. Use of the 19-year cycle after 500 BC does not require the observation of any astronomical cue, either the vernal equinox or the heliacal rising of Perseus—the cycle itself causes the year to begin within half a month of any astronomical cue. The high variability in the interval between intercalary months before 500 BC recorded by Parker and Dubberstein mean that Nisan did occur before the vernal equinox during some years, which is consistent with the heliacal rising of a whole constellation rather than a specific star (like Sirius for the Egyptians). Your rather vague assertion that the year began "about the time of the vernal equinox" during the reign of King Nebuchadnezzar is not contradicted by Parker and Dubberstein. But the Babylonians themselves stated that they used the heliacal rising of stars, not the vernal equinox, to regulate their year before 500 BC. — Joe Kress 08:39, 2 February 2007 (UTC)
Could you please cite at least one Babylonian document where Nisan 1 fell before the vernal equinox? I haven't read what Parker said about Babylonian documents from VI BC, but I know what he noted on the subject of double dated Elephantine papyri where in one case Jews recorded a date suggesting Nisan 1 falling before the vernal equinox - Parker said this only shows they had poor knowledge of Babylonian calendar or made a mistake - please see Sacha Stern, The Babylonian Calendar at Elephantine z Zeitschrift für Papyrologie und Epigraphik 130 (2000) 159-171, as far as I remember Parker's comment is cited somewhere in footnotes. And as far as Jews go, there was no much possibility of greater variation from the time of vernal equinox as all Jewish feasts had to fit in certain seasons of the year to bring the proper kind of crops required by the law or to arrive in Jerusalem when they wouldn't have had to travel in dirt, rain and cold. Isn't that strange that Persians, Babylonians, Israelites, Assyrians and other nations in the regions started their new calendar year about the time of the vernal equinox? It is strange you shift this aside as I have heard the vernal equinox mentioned many times by people writing on the Babylonian calendar. —The preceding unsigned comment was added by Bravehearted (talkcontribs) 19:50, 24 February 2007 (UTC).

Article alterations[edit]

Joe Kress: Don't alter articles when you clearly don't know the subject. You alterations have had to be reversed becuase they are either weak, irrelevant or incorrect. Article writers should be expert before they consider alterations. --Cal Enda Gar (talk) 17:37, 31 July 2008 (UTC)

I assume you have me confused with someone else because I wrote about half the article and that half has not been reverted (most of the first paragraph, all of the paragraph below the table of months, and the Parker and Dubberstein ref). I am readding Chris Bennett's supposedly 'irrelevant' external link because I assume you only read his bare bones Intro page, but did not bother to click on his description of the Babylonian calendar nor on his three century conversion table between Babylonian and Julian dates. However, to avoid the extra step of having to click on his description, I'm changing the link from his introduction to his description. I refrain from explicitly providing a link to the conversion table because he provides it in two formats, Excel and HTML. — Joe Kress (talk) 21:48, 31 July 2008 (UTC)

13 × 28 calendar[edit]

I am removing the following paragraph from the article because the conclusion that the artifact represents a calendar of 13 months of 28 days each is not supported by the reference, which itself has an incorrect title.

Another Western Semitic Calendar in the palace of King Ashurbanipal was based on a year of 13 months of 28 days each to approximate a solar cycle and a month of four weeks of seven days each to approximate a lunar cycle.[Michael Roaf, Cambridge Atlas of Archaeology p.129] It is divided into four quadrants portraying the various seasons in the center and 13 constellations around the outside rim each of which has four holes. Inside of that there is another circular band with 52 holes intended to take pegs. Its layout matches another disk from Crete.

The correct title of the reference is the Cultural Atlas of Mesopotamia and the Ancient Near East. Michael Roaf states on page 129 that the artifact is a "Relief from the palace of Ashurnasirpal (883–859 BC) at Kalhu showing servants preparing food for the king inside a circular camp." He does not even suggest that it is a calendar. A reliable source that states it is a calendar is needed. — Joe Kress (talk) 02:34, 6 February 2009 (UTC)

He doesn't have to suggest it, the illustration is enough click on the link to western semitic calender, then look at the picture and read the description. Rktect (talk) 02:18, 7 February 2009 (UTC)

When anything is challenged in Wikipedia, a reliable source must be provided, otherwise it can be removed. As far as I can see, you invented the term "Western Semitic calendar", and have not provided any reliable source. Your interpretation of Roaf's picture is just that, your interpretation, which Wikipedia considers original research, hence is explicitly forbidden on Wikipedia. I am quite familiar with the Ethiopian calendar and its ancestor, the Alexandrian calendar, since I wrote much of the article. Although many modern Copts and Ethiopians state that it has 13 months, the "13th month" is only 5 or 6 six days, so is certainly not a month in either the solar or lunar sense. Furthermore, its 12 other months have 30 days each, so are certainly not 28 day months. Hence I am removing it from Western Semitic Calendar. I don't see any mention of "a year and a day" in the citation you provided to The 19-year "Metonic" cycle on the Disk. Again, I am quite familiar with the "Metonic cycle" as used in Babylonia, which simply stated that 19 years had 235 months, consisting of 11 common years of 12 lunar months each and 7 leap years of 13 lunar months each. The number of days in either the year or the month were never specified, so "a year and a day", is completely unrelated. On the other hand, the number of days in both the year and month are rigidly specified in the Metonic cycle used to calculate Easter. — Joe Kress (talk) 03:25, 7 February 2009 (UTC)

I'm sure that since you have an interest you want to be certain that before putting something in Wikipedia you know what it is and where its referenced. For me its like describing an architectural style as Greek Revival or Italianate. The essence of the claim is that a set of factors have been identified as present. They are defined under several different systems and attributed to modern philosophers like August Comte, Corporate cultures such as Eastman Kodak, and the artifacts of ancient civilizations such as the Phaistos Disk.

The Positivist calendar was a calendar reform proposal by Auguste Comte in 1849. After revising the earlier work of Marco Mastrofini, Comte's proposed calendar was a solar calendar which had 13 months of 28 days, and an additional festival day commemorating the dead, totalling 365 days.

The International Fixed calendar (also known as the International Perpetual calendar, the Cotsworth plan, the Eastman plan, the 13 Month calendar or the Equal Month calendar) is a proposal for calendar reform providing for a year of 13 months of 28 days each, with one day at the end of each year belonging to no month or week. Though it was never officially adopted in any country, it was the official calendar of the Eastman Kodak Company from 1928 to 1989.[1]...The calendar year has 13 months each with 28 days plus an extra day at the end of the year not belonging to any month. Each year coincides with the corresponding Gregorian year (and so is a solar calendar).

The Lunar_calendaris another Wikipedia site with essentially the same info

In England, a calendar of thirteen months of 28 days each, plus one extra day, known as "a year and a day" was still in use up to Tudor times. This would be a hybrid calendar that had substituted regular weeks of seven days for actual quarter-lunations, so that one month had exactly four weeks, regardless of the actual moon phase. The "lunar year" is here considered to have 364 days, resulting in a solar year of "a year and a day".

According to the links, another illustration of it is the Phaistos Disk.
I just noted that your Babylonian calender has thirteen months and thought you might want to link to the other sites that mention a calender with thirteen months and the rest of the criteria.

The months I'm talking about should not just be thirteen in number but the same length of 28 days, they should be matched to solar and lunar cycles by the addition of one day and they should have 52 weeks in a year, 4 weeks in a month, 4 quarters in a year of 91 days each separate from the months and days. That would be a different system than the Eithiopian calendar despite it has thirteen months.

Since you have been trained by your studies in that field to recognize calendric systems and cycles there should be no question as to what they are. Artifacts of this system are defined simply as a disk divided calendrically into four seasons, thirteen months and 52 weeks. No interpretation is required, does it meet the criteria of the definition or not. The extent of the claim is that there is an object that is as described and illustrated.

I know there are many mentions of thirteen month calenders in Wikipedia, but I don't know that all of them are linked; (some sites have tables). Its an open question as to whether they are or should they be all cross referenced under Positivist CalenderInternational Fixed Calendar, Western Semitic Calendar, Lunar Calendar, Eithiopian Calendar Phaistos Disk Calendar or here in Babylonian calender.
The best descriptions and illustrations of the system are not always found linked to the same sources.
I can't take credit for the invention of any part of that, or for the discussion of a 13 month calender in the various books and publications linked to it there or at other wikipedia cites.
(Neugebauer. ‘The Astronomy of Maimonides and its Sources,’ HUCA 22, 1949.)
Roaf's illustration of it is just an illustration of one example of it. As you appear to be aware thirteen months of twenty eight days are associated with a solar cyccle by the method described below and a month of 28 days is associate with a lunar cycle as a month and a day. I can't claim to know every place it was used but it wasn't an uncommon system.

Rktect (talk) 12:47, 7 February 2009 (UTC)

Rktect's article on his 'Western Semitic calendar' has been deleted as his own original research, he himself was banned yesterday indefinitely for original research over the past 3 1/2 years. dougweller (talk) 09:37, 12 February 2009 (UTC)

Intercalary Month in year seventeen[edit]

I am making a calendar converter using algorithms from Dershowitz and Reingold in an Excel spreadsheet. They don't have algorithms for the Babylonian calendar so I am using the Hebrew calendar algorithms and taking out the adjustments. I would like to know what the intercalary month in year 17 was called. Would I be right in assuming that if the regular month Adar is called, Araḫ Addaru or Araḫ Adār, and the intercalary month Adar is called, Araḫ Makaruša Addari or Araḫ Ve-Adār, which I assume means "Second month Adar", then the month Araḫ Ulūlu, would be called Araḫ Makaruša Ulūli or Araḫ Ve-Ulūlu, "Second Month Ululu", when it is the intercalary month. Google translator doesn't do Babylonian. alexselkirk1704@hotmail.com Alexselkirk1704 (talk) 05:59, 16 October 2011 (UTC)

Assyrologists usually refer to these months as Addaru II and Ululu II. See the link to the Babylonian calendar converter (based on the 1956 Parker & Dubberstein tables) at the bottom of the page. AstroLynx (talk) 16:18, 25 October 2011 (UTC)