Drought and the Dresden Codex Venus Table. (06/11/2001)

Scientists at the University of Florida (Geology Department) have recently published a paper (Science v292: May 2001, pp.1367-1370) outlining the discovery of a tropical drought cycle that affected Central America every 208 years. The study ("Solar Forcing of Drought Frequency in the Maya Lowlands" by David A Hodell, Mark Brenner, Jason H. Curtis, and Thomas Guilderson) analyses core samples taken from Lake Chichancanab in northern Yucatan which detail gypsum deposits on the lake's bed over a period of 2,600 years. The layers of gypsum are thickest in the core sample when the ratio of rainfall to evaporation over the lake is highest. In other words, during the driest years the amount of evaporation in the lake was at its highest level, a fact which caused the release of greater amounts than average of gypsum as sediment. The core samples were dated using standard techniques (Carbon 14, for instance) to analyze organic material found in the samples.

Two significant "historical" markers were discovered in the study. According to analysis of the core samples, a drought event between 125 AD and 210 AD very probably occurred. This coincides with long-accepted archeological evidence which suggests that "a severe dry period at El Mirador, northern Guatemala, . . . may have contributed to the site's abandonment around 150 AD" (1367). In other words, the core samples support the idea that prolonged drought may have been a contributing factor to the collapse of pre-Classic Maya civilization. Also true is the fact that another such period of severe drought occurred in the samples between 750 AD and 1025 AD. This time-frame corresponds to the collapse of Classic period Maya civilization and the authors suggest that this second period of drought in the region probably contributed to that abandonment as well.

In their concluding summary of the data gathered, the authors state that "the large bicentennial-scale events [208 years long] were often composed of multiple 50-year oscillations" (1370). While I am not absolutely certain I understand what this statement means, and assume that each 208-year period had alternating dry and wet sequences of approximately 50 years in duration, I could not help but be struck by the parallel that exists between the drought cycle identified in Science and the essential structure of the Maya's Dresden Codex Venus Table (pp. 46-50), which depends on two Calendar Round intervals of 52 Maya solar years (at 365 days each) to complete its total interval of 37,960 days from one base-day to the next. Since each Table is 104 years long, two turns of its structure would be equivalent to one 208-year drought cycle with four parts of 52 years each. While this parallel might only be coincidental, and not overtly intentional, in the sense that one probably cannot assert that the Table was designed specifically to monitor the occurrence of drought events during the Classic period, the fact remains that the authors of the Dresden text did include a firm and well-established connection between Venus positions and drought occurrences in its articulation.

According to Eric Thompson (Maya Hieroglyphic Writing, 1970), for instance, the days in the Dresden Venus table which were identified with the planet's "heliacal rising" (218) in his correlation (584283 as the Ahau constant at 4 Ahau 8 Cumku) were also the days on which Venus exerted its most malevolent aspect toward the fortunes of human endeavors in the world at large. In the Goodman-Martinez-Thompson (GMT) correlation, "heliacal rising" occurred on the fourth day of each synodic period of the planet as the Maya recorded them over the five pages (46-50) of the Dresden Codex. Those five positions fell in sequence at pp. 46D (lines 1-13) on the Tzolkin day-name Kan with the Haab designation 12 Yax, at 47H (lines 1-13) on the Tzolkin day-name Lamat with the Haab designation 6 Zip, at 48L (lines 1-13) on Eb day-names with 5 Kankin in the Haab, at 49P (lines 1-13) on Cib day-names with 19 Xul, and finally, at 50T (lines 1-13) on Ahau day-names with 18 Kayab. The base-day of the Table was recorded as 1 Ahau 18 Kayab, the designation for which occurred at 50T, line 13, in the text and which stands as the final day-name recorded in the Table's overall structure. The interval separating these Tzolkin day-names (Kan, Lamat, Eb, Cib, and Ahau) in vertical columns of the Table with these specific Haab designations (12 Yax, 6 Zip, 5 Kankin, 19 Xul, and 18 Kayab respectively) is equal to 2,920 days, or 8 x 365 = 5 x 584 days. What this structure accomplishes, in terms of Venus's motion, is to fix its position relative to the sun and the stellar background, in a general sense, over long periods of time.

In Thompson's analysis of Seler's ("Venus Period in the Picture Writings of the Borgian Codex Group"; in Bureau of American Ethnology, Bulletin 28, pp. 353-391, Washington D. C.) discussion of Venus tables in the Mexican Codices (Thompson 217-218), he notes that the fifth day-name (Ahau with 18 Kayab in the Dresden text) was the one most closely associated with drought events in the text. In the 12 Lamat Eclipse correlation (563334 as the Ahau constant at 4 Ahau 8 Cumku), the base-day for the Dresden Codex Venus Table at 1 Ahau 18 Kayab falls on September 27, 565 AD (Julian Day #1927694) with Venus at 46.1 of elongation in the morning sky six days prior to its maximum western elongation from the sun (at 46.5 on October 3, 565 A. D.-Julian Day #1927700). In the GMT correlation, this same position (1 Ahau 18 Kayab) falls approximately 58 years later on February 4, 623 A. D. (Julian calendar) on Julian Day #1948643 with Venus at 23.8 of elongation from the sun in the evening sky but 16 days prior to its "heliacal rising" (on February 20, 623 A. D.-Julian Day #1948659). Thompson, and others, have presented various justifications and rationalizations to account for this obvious disparity in their claims that the GMT correlation satisfies all necessary conditions in Maya astronomy (namely that 1 Ahau 18 Kayab is the day of Venus's "heliacal rising") to establish and confirm 584283 as the zero base-day for the Long Count notation ( 4 Ahau 8 Cumku) during the Classic period.

The position taken here with respect to this problem is that, since the Dresden text itself does not specify which position of Venus actually fell at the base-day of the structure, and since the GMT correlation does not even satisfy its own most definitive conditions (ones derived from ethnohistorical data), a different evaluation for that position is not only possible but also necessary. A significant advantage in the Venus position established by the 12 Lamat Eclipse correlation, as opposed to the one in the GMT, is that a more consistently stable relationship between Venus and the sun occurs when the base-day of the Table is set to record a stationary position of the planet near one of its maximum elongations from the sun. In this particular case, where Venus reaches the first of 10 days during which it remains fixed at 46.5 of elongation from the sun in the morning sky six days after the base-day, and does not return to its starting point at 46.1 until 23 days have passed (on October 20, 565 AD-Julian Day #1927717), a virtually ideal circumstance is achieved because a 10-day interval for maximum elongation is the longest one that occurs for that position over time. The circumstance is said to be ideal if the objective of the Table's structure is to "freeze" Venus's position on specific day-names (at intervals of 8 x 365 = 5 x 584 = 2,920 days) over long periods of time. This is precisely what the Table's structure achieves and it seems appropriate to characterize that function as intentional, as opposed to merely accidental.

Given the facts in hand, then, the possibility exists that the drought interval would have become apparent to the Maya in the context of a pre-existing tabular structure, like the Dresden Codex Venus Table, at some point during their history, since both the period of oscillation (50 years) and the interval of severe drought events (208 years) are relatively the same as the ones that define the motion of Venus relative to the sun in the calendrical structure they used from the end of the pre-Classic to the terminal point of the subsequent Classic period. Using the date given by Hodell, et. al., in their study as a point of departure from the onset of the drought at the end of the pre-Classic phase of Maya civilization (125 AD), the Venus Table position that best fits the criteria, including the drought-designation in the text itself, fell at 3 Ahau 18 Kayab on January 15, 126 AD (Julian Day #1767094). This day-name was recorded on page 50, column T, line 10, in the text and marked the fourth day of the 50th synodic period of the planet in the Table's structure. 24 years (at 365 days each) and 15 synodic periods (at 584 days each) of the planet later, on January 9, 150 AD (Julian Day #1775854), the then current base-day of the Dresden Codex Venus Table would have been counted at 4 x 37,960 days prior to the date recorded for 1 Ahau 18 Kayab in the actual text itself. Hence, 1 Ahau 18 Kayab is consistent with the base-day sequence of the Dresden Venus Table, falls in the proper time-frame for the drought, and matches the accepted date for the abandonment of El Mirador at the end of the pre-Classic phase of Maya civilization.

Virtually the same sequence of events and calendar designations for them can be seen 600 years later at the terminal point of the Classic period. Just as significant, however, and in remarkable consistency with this same pattern, are two other events in Maya history that can be said to have shaped its destiny during the Classic period. 208 years after the initiation of the drought sequence that terminated the pre-Classic period, a second such event began on November 24, 333 AD (Julian Day #1843014) when the Maya Venus Table again reached 3 Ahau 18 Kayab ( in the Long Count notation). Approximately six years later, at 5 Cimi 14 Kayab (November 14, 339 AD-Julian Day #1845200) Bahlum-Kuk was born in Palenque, Chiapas, Mexico. This individual, whose "birth" date was recorded in the inscription in the Temple of the Cross, became the founder of the ruling dynasty at the ceremonial center which lasted until the end of the Classic period. As noted earlier, 24 years and 15 synodic periods of Venus after 3 Ahau 18 Kayab the base-day of the Dresden Venus Table was again reached at 1 Ahau 18 Kayab on November 18, 357 AD (Julian Day #1851774). The earlier base-day, at 1 Ahau 18 Kayab, can be said to mark the terminal point of the pre-Classic period with the abandonment of El Mirador. This one, 208 years later, can be said to anticipate the accession ritual of Bahlum-Kuk at Palenque because that event fell 16 days prior to a formal position in the Venus Table at the end of the tenth synodic period of the planet, and 16 years after the base-day of the Table, at 4 Ahau 18 Kayab on November 14, 373 AD (Julian Day #1857614). The accession ritual itself came at 1 Kan 2 Kayab on October 29, 373 AD (Julian Day #1857598). Given the relatively close proximity of Bahlum-Kuk's accession, and the founding of Palenque's dynasty, to the formal structure of the Venus Table at 4 Ahau 18 Kayab, and by extension to the drought sequence identified in the core samples from Lake Chichancanab, there seems to be some sense of connection here between the end of one era (pre-Classic) and the beginning of the next one (Classic) as expressed in the way the Maya may have perceived a fundamental relationship between the malevolent influences of Venus as a cause of natural conditions associated with the fall and rise of their cultural imperatives. This also raises curious questions about the assumption that this drought sequence produced only negative effects in the region, since Bahlum-Kuk's accession does stand at the beginning of the highest level of cultural achievement of Maya civilization as a whole.

This same impression is reinforced by the second event that can be associated with this parallel between drought events and Palenque's dynastic history. This is true because the next leap forward from the base-day of the Venus Table here (at 1 Ahau 18 Kayab) reaches 1 Ahau 18 Kayab on September 27, 565 AD (Julian Day #1927694) which is the actual position of the base-day for the Table as it was recorded in the Dresden Codex itself. The position previously identified as being consistent with the beginning of the drought sequence in both earlier cases (at 3 Ahau 18 Kayab) fell here at in the Maya Long Count notation on October 3, 541 AD (Julian Day #1918934). This position is significant in Palenque's dynastic history because it fell 1,500 days prior to the "birth" date of Pacal II, at 8 Ahau 13 Pop on November 11, 545 AD (Julian Day #1920434), who has come to be recognized as that ceremonial center's greatest and most powerful ruler. Hence, the previous initiation of the drought sequence marked the beginning of Palenque's dynastic history and this one marked the point in time when it reached its apogee. Again, the drought seems to have produced a limited, if not shallow, effect on the economic and political fortunes of Maya civilization.

The date for the drought sequence itself that began prior to the terminal date of the Classic period, like each of those discussed above, came at 3 Ahau 18 Kayab on August 12, 749 AD (Julian Day #1994854). Core sample data place the beginning of the drought in 750 AD. 24 years and 15 synodic periods of Venus later, the next base-day of the Dresden Codex Venus Table fell at 1 Ahau 18 Kayab on August 6, 773 AD (Julian Day #2003614). This date is consistent with the time-frame for the termination of the kind of social and cultural activity associated with Classic period Maya civilization.

Data in the following table illustrates the progression of drought sequences in the context of the Dresden Codex Venus Table as it would have been written from 125 AD to 773 AD. The third day-name with each pair (3 Ahau and 1 Ahau with 18 Kayab) shows the interval from the Dresden Codex Venus Table base-day to the first day of each maximum western elongation after the Venus positions marked by the Table's formal designation.

Maya LC Notation
Julian Day Number
Julian Date
Page Column Line in the DCVT
Venus elongation position 3 Ahau 18 Kayab 1767094January 15, 126 50T10Venus 40.2 Msky
+ 8,760 1 Ahau 18 Kayab 1775854January 9, 150 50T13Venus 40.9 Msky
+ 29 4 Muluc 2 Pop 1775883February 7, 150 Venus 46.6 Msky MWE
+37,960 3 Ahau 18 Kayab 1805054December 20, 229 50T10Venus 42.9 Msky
+ 8,760 1 Ahau 18 Kayab 1813814December 15, 253 50T13Venus 43.6 Msky
+ 26 1 Cimi 4 Uayeb 1813840January 10, 254 Venus 46.9 Msky MWE
+37,960 3 Ahau 18 Kayab 1843014November 24, 333 50T10Venus 44.6 Msky
+ 8,760 1 Ahau 18 Kayab 1851774November 19, 357 50T13Venus 45.1 Msky
+ 17 5 Caban 15 Cumku 1851791December 5, 357 Venus 46.9 Msky MWE
+37,960 3 Ahau 18 Kayab 1880974October 29, 437 50T10Venus 45.7 Msky
+ 8,760 1 Ahau 18 Kayab 1889734October 23, 461 50T13Venus 45.8 Msky
+ 12 13 Eb 10 Cumku 1889746November 4, 461 Venus 46.8 Msky MWE
+37,960 3 Ahau 18 Kayab 1918934October 3, 541 50T10Venus 46.1 Msky
+ 8,760 1 Ahau 18 Kayab 1927694September 27, 565 50T13Venus 46.1 Msky
+ 10 11 Oc 8 Cumku 1927704October 7, 565 Venus 46.6 Msky MWE
+37,960 3 Ahau 18 Kayab 1956894September 7, 645 50T10Venus 46.1 Msky
+ 8,760 1 Ahau 18 Kayab 1965654September 1, 669 50T13Venus 46.1 Msky
+ 2 3 Ik 0 Cumku 1965656September 3, 669 Venus 46.2 Msky MWE
+37,960 3 Ahau 18 Kayab 1994854August 12, 749 50T10Venus 46.0 Msky
+ 8,760 1 Ahau 18 Kayab 2003614August 6, 773 50T13Venus 45.9 Msky
- 3 11 Caban 15 Kayab 2003611August 3, 773 Venus 45.9 Msky MWE

While the data presented here does not necessarily prove that Classic period Maya astronomers designed the Dresden Codex Venus Table specifically to count the intervals between potentially destructive drought events, where the Venus elongation positions themselves account for the purpose behind the Table's structure, it is nevertheless true that the base-day positions (at 1 Ahau 18 Kayab) are consistently positioned (at 24 x 365 and 15 x 584) at a time when a drought event would have become severe enough (after its initial beginning at 3 Ahau 18 Kayab) to precipitate serious disruptions in a culture that depended on agricultural production for its social health and survival. Because the first event in 125 AD works forward to the year in which most scholars fix the abandonment of El Mirador and the end of the pre-Classic period (150 AD), where the interval between drought events is equal to 208 years, every other subsequent base-day in the Venus Table also marks the point at which subsequent drought events reached a critically disruptive phase. The point here, of course, is that the base-day of the Venus Table, which is associated with droughts in the text itself, could have been used by the Maya to predict the occurrence of the drought sequences found in the gypsum deposits from Lake Chichancanab as reported by Hodell, et. al., in Science. To say that Western scientists discovered an ancient drought sequence in core samples from the Lake, therefore, may not be precisely accurate, since an argument can be put that they merely confirmed the existence of a natural phenomena already known to and articulated by Classic period Maya calendricists in the structure and text of the Dresden Codex Venus Table itself.

Also apparent here is the fact that two subsequent drought events after the abandonment of El Mirador fell in reasonable proximity to the "birth" dates of Palenque's founding ruler (Bahlum-Kuk) and its most powerful king (Pacal II). What this may suggest is that Maya civilization was not held hostage to cyclical weather patterns and was able to withstand even the most severe conditions as they arose. A final fact which might imply the Maya were aware of the drought sequence emerges at the end of Palenque's Classic period dynastic history. That ceremonial center's final ruler, 6-Cimi Pacal, acceded to the throne at 7 Kan 17 Muan on July 4, 742 AD (Julian Day #1992258). There is no record of his death date in the inscriptions and it seems reasonable to suppose, since 7 Kan 17 Muan was the last date recorded at Palenque, that the center was abandoned soon after that date. With respect to the Venus Table itself, the accession of 6-Cimi Pacal occurred just two days before 9 Cimi 19 Muan, which is a formal position in the Dresden Codex Venus Table at the second station of the 46th synodic period of the planet. This is just four periods of the planet prior to 3 Ahau 18 Kayab (August 12, 749 AD) which marks the initiation of the drought sequence that terminated the Classic period. While the two-day differential between these two dates may be nothing more than coincidence, Palenque's prior dynastic history tends to support the notion that the Venus Table did play a significant role in its dynastic evolution, and one that may well have been connected in some way to the drought sequence identified in the core samples of Lake Chichancanab.