37
but we do not know whether they were ever used in practice. Beginning in the early
fifth century BC, however, a fixed 19-year cycle of intercalation was adopted and,
as far as we can tell, operated without interruption until the end of our sources in the
first century AD (Britton, 2007; Ossendrijver, 2018). According to this cycle, 7 years
out of every nineteen contained an intercalary month.
One result of intercalation, whether it was governed by royal decision or followed a regular cycle, was to keep the beginning of the year fairly near to the date
of the vernal equinox. We should not a priori assume, however, that keeping the
beginning of the year aligned with the equinox was the intention of the
Mesopotamians: the desire may simply have been to keep the beginning of the year
in the early spring and the fact that this is close to the date of the vernal equinox is
a by- product of that decision.
Luni-solar calendars, especially those based upon observing the new moon crescent and which have irregular intercalation, make the calculation of things like
interest on loans and the payment of rations difficult. Almost certainly for this reason, therefore, a simplified “schematic” calendar was used in many administrative
and astronomical contexts. This calendar simply assumed that each month contained 30 days and that there are always 12 months in the year, making a total of
360 days (Brack-Bernsen, 2007; Steele, 2011). This 360-day calendar also appears
in certain literary and religious texts where it seems to represent the “ideal” state of
the universe at creation (Brown, 2000). It is important to stress, however, that this
schematic 360-day calendar, although appearing frequently in early astronomical
texts, never operated as a real calendar, nor was 360 days ever thought to the actual
length of the year. Instead, it always acted purely as a computational device to simplify calculations.
3 The Early Second Millennium BC
Two compositions preserved in Old Babylonian copies contain the earliest references to solstices and equinoxes: a small part of a Sumerian literary composition
concerning the goddess Inana (Brown & Zólyomi, 2001), and an Akkadian text
which presents a scheme for the change in the length of day and night over the schematic year (Hunger & Pingree, 1989: 163–164). Neither text refers to the solstices
or equinox by name but both are concerned with the length of night on one or more
of the solstices or equinoxes.
The relevant part of the Sumerian composition concerning Inana is preserved in
two copies. The two manuscripts show some differences, most significantly in
switching the order of the two lines relevant to us. These differences do not change
the overall content of the passage, however. The passage can be transliterated and
translated as given below. The transliteration is a composite of the two sources as
reconstructed by Brown and Zólyomi (2001) except that I have reversed the order of
the two lines (following their MS B) because the text seems to make better sense
ordered this way. The translation follows Brown and Zólyomi (2001) except in
Their Equinox: Mesopotamian Conceptions of Solstices and Equinoxes
but we do not know whether they were ever used in practice. Beginning in the early
fifth century BC, however, a fixed 19-year cycle of intercalation was adopted and,
as far as we can tell, operated without interruption until the end of our sources in the
first century AD (Britton, 2007; Ossendrijver, 2018). According to this cycle, 7 years
out of every nineteen contained an intercalary month.
One result of intercalation, whether it was governed by royal decision or followed a regular cycle, was to keep the beginning of the year fairly near to the date
of the vernal equinox. We should not a priori assume, however, that keeping the
beginning of the year aligned with the equinox was the intention of the
Mesopotamians: the desire may simply have been to keep the beginning of the year
in the early spring and the fact that this is close to the date of the vernal equinox is
a by- product of that decision.
Luni-solar calendars, especially those based upon observing the new moon crescent and which have irregular intercalation, make the calculation of things like
interest on loans and the payment of rations difficult. Almost certainly for this reason, therefore, a simplified “schematic” calendar was used in many administrative
and astronomical contexts. This calendar simply assumed that each month contained 30 days and that there are always 12 months in the year, making a total of
360 days (Brack-Bernsen, 2007; Steele, 2011). This 360-day calendar also appears
in certain literary and religious texts where it seems to represent the “ideal” state of
the universe at creation (Brown, 2000). It is important to stress, however, that this
schematic 360-day calendar, although appearing frequently in early astronomical
texts, never operated as a real calendar, nor was 360 days ever thought to the actual
length of the year. Instead, it always acted purely as a computational device to simplify calculations.
3 The Early Second Millennium BC
Two compositions preserved in Old Babylonian copies contain the earliest references to solstices and equinoxes: a small part of a Sumerian literary composition
concerning the goddess Inana (Brown & Zólyomi, 2001), and an Akkadian text
which presents a scheme for the change in the length of day and night over the schematic year (Hunger & Pingree, 1989: 163–164). Neither text refers to the solstices
or equinox by name but both are concerned with the length of night on one or more
of the solstices or equinoxes.
The relevant part of the Sumerian composition concerning Inana is preserved in
two copies. The two manuscripts show some differences, most significantly in
switching the order of the two lines relevant to us. These differences do not change
the overall content of the passage, however. The passage can be transliterated and
translated as given below. The transliteration is a composite of the two sources as
reconstructed by Brown and Zólyomi (2001) except that I have reversed the order of
the two lines (following their MS B) because the text seems to make better sense
ordered this way. The translation follows Brown and Zólyomi (2001) except in
Their Equinox: Mesopotamian Conceptions of Solstices and Equinoxes