I follow Roman calendar where new year starts in March.
1 March
2 April
3 May
4 June
5 July
6 August
7 September
8 October
9 November
10 December
11 January
12 February
The first month in the OT bible is Nissan. Wikipedia: "Nisan (or Nissan; Hebrew: נִיסָן, Standard Nīsan, Tiberian Nīsān; from Akkadian: 𒊬𒊒𒄀 Nisanu) in the Babylonian and Hebrew calendars is the month of the barley ripening and first month of spring. The name of the month is an Akkadian language borrowing, although ultimately originates in Sumerian nisag "first fruits". In the Hebrew calendar it is the first month of the ecclesiastical year, called the "first of the months of the year" (Book of Exodus 12:1-2), "first month" (Ex 12:14), and the month of Aviv (Ex 13:4) בְּחֹ֖דֶשׁ הָאָבִֽיב ḥōḏeš hā-’āḇîḇ).
It is called Nisan in the Book of Esther in the Tanakh and later in the Talmud, which calls it the "New Year", Rosh HaShana, for kings and pilgrimages. It is a month of 30 days. Nisan usually falls in March–April on the Gregorian calendar. Counting from 1 Tishrei, the civil new year, it would be the seventh month (eighth, in leap year), but in contemporary Jewish culture, both months are viewed as the first and seventh simultaneously, and are referred to as one or the other depending on the specific religious aspects being discussed."
The Talmudic Rabbinical Jewish new year is Rosh HaShana, head of the year, which is Babylonian harvest festival celebrated at the end of the year. Wikipedia: "The biblical name for this holiday is Yom Teruah (יוֹם תְּרוּעָה, Yōm Tərūʿā, lit. "day of shouting/blasting") It is the first of the Jewish High Holy Days (יָמִים נוֹרָאִים, Yāmīm Nōrāʾīm, "Days of Awe"), as specified by Leviticus 23:23–25, that occur in the late summer/early autumn of the Northern Hemisphere."
So, the original pre-Babylonian exile biblical months are numerical, 1st month being in Spring, later called Nissan, as returning from Babylon Jews brought with them the mathematical calendar, original biblical calendar is based on the agricultural observations, the months names after the Babylonian gods have replaced the numerical order, and the new year moved from Spring of the first month to the Autumn of the seventh month in tune with the Babylonian traditions.
Wikipedia: "The present Hebrew calendar is the result of a process of development, including a Babylonian influence. Until the Tannaitic period (approximately 10–220 CE), the calendar employed a new crescent moon, with an additional month normally added every two or three years to correct for the difference between the lunar year of twelve lunar months and the solar year.
The year in which it was added was based on observation of natural agriculture-related events in ancient Israel. Through the Amoraic period (200–500 CE) and into the Geonic period, this system was gradually displaced by the mathematical rules of the Metonic cycle used today. The principles and rules were fully codified by Maimonides in the Mishneh Torah in the 12th century. Maimonides' work also replaced counting "years since the destruction of the Temple" with the modern creation-era Anno Mundi.
The Hebrew lunar year is about 11 days shorter than the solar year and uses the 19-year Metonic cycle to bring it into line with the solar year, with the addition of an intercalary month every two or three years, for a total of seven times per 19 years. Even with this intercalation, the average Hebrew calendar year is longer by about 6 minutes and 40 seconds than the current mean tropical year, so that every 216 years the Hebrew calendar will fall a day behind the current mean tropical year.
The era used for the calendar since the Middle Ages is Anno Mundi (Latin: "in the year of the world"; Hebrew: לבריאת העולם, "from the creation of the world"). As with Anno Domini (A.D. or AD), the words or abbreviation for Anno Mundi (A.M. or AM) for the era should properly precede the date rather than follow it. The epoch of this era is the moment when, according to the Genesis creation narrative, the world was created. AM 5783 began at sunset on 25 September 2022 and will end at sunset on 15 September 2023."
The Byzantine calendar has AM 7,531 as the current year 2022. Wikipedia: "The Byzantine calendar, also called the Roman calendar, the Creation Era of Constantinople or the Era of the World (Ancient Greek: Ἔτη Γενέσεως Κόσμου κατὰ Ῥωμαίους, also Ἔτος Κτίσεως Κόσμου or Ἔτος Κόσμου, abbreviated as ε.Κ.; literal translation of Ancient Greek Roman year since the creation of the universe), was the calendar used by the Eastern Orthodox Church from c. 691 to 1728 in the Ecumenical Patriarchate. It was also the official calendar of the Byzantine Empire from 988 to 1453 and of Kievan Rus' and Russia from c. 988 to 1700.
This calendar was used also in other areas of the Byzantine commonwealth such as in Serbia, where it is found in old Serbian legal documents such as Dušan's Code, thus being referred to as the Serbian Calendar as well. Since Byzantine is a historiographical term, the original name uses the adjective "Roman" as it was what the Eastern Roman Empire continued calling itself.
The calendar was based on the Julian calendar, except that the year started on 1 September and the year number used an Anno Mundi epoch derived from the Septuagint version of the Bible. It placed the date of creation at 5509 years before the incarnation of Jesus, and was characterized by a certain tendency that had already been a tradition among Jews and early Christians to number the years from the calculated foundation of the world (Latin: Annus Mundi or Ab Origine Mundi— "AM"). Its Year One, marking the supposed date of creation, was September 1, 5509 BC, to August 31, 5508 BC. This would make the current year (AD 2022) 7531 (7530 before September 1; and 7531 after September 1)."
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