39
[From Month VI day 1]5 to Month IX day 15 is 3 months. [On Month IX day 15, 1 (of) the
wat]ch of the day coverts into night. [… 2] is the watch of the day, 4 is the watch of the
night.
------------------------------------------------------------------------------------------------------------[From Month IX day 15 t]o Month XII day 15 is 3 months. [On Month XII day 15 1 (of) the
wat]ch of the night converts into day. [… 3] is the watch of the day, 3 is the watch of the
night. [Day and night] are equal.
The text presents a scheme giving the length of day and night on the 15th of
Months III, VI, IX and XII. On the 15th of Months XII and VI day and the night are
said to be of equal length. As in the previous text, this length is given as three
without a unit (it can again be assumed to refer to either 3 mina or 3,0 UŠ), and
therefore corresponds to the equinox. On the 15th of Month III, day is said to be of
length 4 and night of length 2. These lengths of day and night are reversed on the
15th of Month IX. Thus, the summer solstice is taken to be on the 15th of Month III
and the winter solstice on the 15th of Month IX. The scheme states that between the
summer solstice in Month III and the winter solstice in Month IX part of the day is
converted into night, and vice versa between winter solstice and the summer solstice. Comparison with later texts makes it almost certain that the length of day and
night are assumed to vary linearly between the extremes of 2 and 4 at the solstices
and that the dates given in the scheme are to be understood as being within the schematic 360-day calendar. These extremes are greatly exaggerated for the latitude of
anywhere within Mesopotamia and seem to have been chosen for their simplicity
(Brown, Fermor, & Walker, 1999–2000).
Both the passage in the Sumerian literary text and the scheme on BM
17175 + 17284 show a concern with the length of day and night. In BM 17175 + 17284
the length of day and night is connected to four equally-spaced dates in the schematic calendar. Thus, although the texts do not name these dates as the solstices and
equinoxes, it is clear that what is of interest to the authors of these texts are the occasions when day and night are of equal length or when they are their shortest and
longest. For these authors, therefore, solstices and equinoxes are defined by the
length of day and night and, secondarily, by equal divisions of the schematic year.
4 The Late Second and Early First Millennium BC
Table C of the fourteenth tablet of the celestial omen series Enūma Anu Enlil (AlRawi & George, 1991–1992) contains a list of length of day and night on the 15th
and 30th day of each month in the schematic 360-day calendar. The date of composition of Enūma Anu Enlil is not known but must lie somewhere in the late second
or early first millennium BC; the work was already widely known and copied by the
beginning of the seventh century BC. According to this text the lengths of day and
night follow zigzag functions with maximum and minimum 4 mina and 2 mina. The
scheme is clearly an elaboration of that found on the Old Babylonian tablet BM
17175 + 17284 discussed in Sect. 3, extended to give values for the schematic dates
Their Equinox: Mesopotamian Conceptions of Solstices and Equinoxes
[From Month VI day 1]5 to Month IX day 15 is 3 months. [On Month IX day 15, 1 (of) the
wat]ch of the day coverts into night. [… 2] is the watch of the day, 4 is the watch of the
night.
------------------------------------------------------------------------------------------------------------[From Month IX day 15 t]o Month XII day 15 is 3 months. [On Month XII day 15 1 (of) the
wat]ch of the night converts into day. [… 3] is the watch of the day, 3 is the watch of the
night. [Day and night] are equal.
The text presents a scheme giving the length of day and night on the 15th of
Months III, VI, IX and XII. On the 15th of Months XII and VI day and the night are
said to be of equal length. As in the previous text, this length is given as three
without a unit (it can again be assumed to refer to either 3 mina or 3,0 UŠ), and
therefore corresponds to the equinox. On the 15th of Month III, day is said to be of
length 4 and night of length 2. These lengths of day and night are reversed on the
15th of Month IX. Thus, the summer solstice is taken to be on the 15th of Month III
and the winter solstice on the 15th of Month IX. The scheme states that between the
summer solstice in Month III and the winter solstice in Month IX part of the day is
converted into night, and vice versa between winter solstice and the summer solstice. Comparison with later texts makes it almost certain that the length of day and
night are assumed to vary linearly between the extremes of 2 and 4 at the solstices
and that the dates given in the scheme are to be understood as being within the schematic 360-day calendar. These extremes are greatly exaggerated for the latitude of
anywhere within Mesopotamia and seem to have been chosen for their simplicity
(Brown, Fermor, & Walker, 1999–2000).
Both the passage in the Sumerian literary text and the scheme on BM
17175 + 17284 show a concern with the length of day and night. In BM 17175 + 17284
the length of day and night is connected to four equally-spaced dates in the schematic calendar. Thus, although the texts do not name these dates as the solstices and
equinoxes, it is clear that what is of interest to the authors of these texts are the occasions when day and night are of equal length or when they are their shortest and
longest. For these authors, therefore, solstices and equinoxes are defined by the
length of day and night and, secondarily, by equal divisions of the schematic year.
4 The Late Second and Early First Millennium BC
Table C of the fourteenth tablet of the celestial omen series Enūma Anu Enlil (AlRawi & George, 1991–1992) contains a list of length of day and night on the 15th
and 30th day of each month in the schematic 360-day calendar. The date of composition of Enūma Anu Enlil is not known but must lie somewhere in the late second
or early first millennium BC; the work was already widely known and copied by the
beginning of the seventh century BC. According to this text the lengths of day and
night follow zigzag functions with maximum and minimum 4 mina and 2 mina. The
scheme is clearly an elaboration of that found on the Old Babylonian tablet BM
17175 + 17284 discussed in Sect. 3, extended to give values for the schematic dates
Their Equinox: Mesopotamian Conceptions of Solstices and Equinoxes