The “Era” Date on Coba, Stela 5

Coba, Stela 5 is one of three remarkable monuments at the site that record the full, unabridged “era” date using all 24 periods of what I call the “Grand Long Count.” (The other monuments are Stelae 1 and 27). This immense span of time we can transcribe as
4 Ajaw 8 Kumk’u

In this note I would like to point out a couple of interesting features of this date on Stela 5, as well to a problem evident in its published drawing (Graham 1997:36), traceable in turn to an error in the restoration of the stela’s fragments done around 1980.

Figure 1. Coba Stela 5, right side, with correction to the lower glyph blocks. Drawing by Ian Graham (from Graham 1997:36).

If we look closely at the published drawing (Figure 1a, at left) we can see that the final components of the Grand Long Count, although damaged by a break in the stone, include the familiar K’atun and K’in periods at the blocks Qp11 and Pp14. However, there are two too many intervening glyphs in what are labelled as rows 12 and 13, where only the Tun and Winal periods would be expected. Close inspection of the photograph shows that this is in fact due to an unfortunate gap created by a faulty modern restoration of the stela’s two main fragments. That is, rows “12” and “13” look to actually encompass a single row of two glyphs that was poorly fitted together during restoration (Figure 2). Once corrected (as shown in Figure 1b), the two glyph blocks can easily accommodate the expected Tun and Winal periods and make for a perfectly acceptable date overall, with a proper tally of twenty-four periods.
Figure 2. Detail of photograph of Coba Stela 5 text (from Graham 1997)

Two interesting features of the extended Long Count date stand out. The most obvious is the conch shell form of the “Bak’tun” sign as Pp11 — a unique occurrence in all Maya inscriptions, for which I have no explanation. The other noteworthy aspect of the full date concerns the orientations of the many “13” coefficients. There are twenty in all (Pp1 is surely an ISIG glyph) but just two show the number as a horizontal prefix, as seen in the seventh unit at Qp4 and with the Bak’tun at Pp11; all other 13 prefixes are vertical. Again I have no explanation for this odd feature (horizontal numbers do not appear on the other “era” dates recorded at Coba) but it’s probably significant that these two examples are spaced thirteen units apart. That is to say, the higher of these units is thirteen positions above the Bak’tun. I suspect that these horizontal number coefficients served as visual cues, used by the scribes to subtly mark an internally significant structure to the extended calendar system. It’s worth noting, too, that the corrected fit of the stela fragments produces thirteen rows of glyphs in the record of this important date — surely not a coincidence.


Graham, Ian. 1997. Corpus of Maya Hieroglyphic Inscriptions, Volume 8, Part 1: Coba. Cambridge: Peabody Museum of Archaeology and Ethnology, Harvard University.

5 thoughts on “The “Era” Date on Coba, Stela 5

  1. Lorna Huff April 25, 2010 / 3:22 PM

    Dear David,

    Thanks for your response on my previous query. It can be no small task to do a drawing from Coba! With respect for Stela 5 at Coba, I wonder if the unique conch shell “Bak’tun” at Pp11 could also signify the loud sound made by a conch shell as a trumpet, perhaps to signal a ‘completion’ position within the Grand Long Count series ? It seems meaningful in an auditory sense, stimulated by a visual cue. Perhaps the text was read orally with musical accompaniment? It seems JUB’ (T579v), a “shell” or “shell trumpet”, (possibly representing the cross-section of a shell as noted by JM), quite resembles the shape of the “Bak’tun” conch shell.


  2. Miriam May 1, 2010 / 6:37 PM

    In what Mayan language are the translations made? Quiche?

    • David Stuart June 17, 2010 / 6:48 PM

      The language isn’t Quiche (K’iche’), but rather an ancient language we associate with the Ch’olan-Tzeltalan group. Today this group includes Ch’ol, Ch’orti’, Chontal, as well as Tzeltal, Tzotzil and Tojolab’al. The language of the ancient inscriptions was ancestral to one or more of these, although epigraphers and linguists continue to try to figure out the precise historical relationships between them.

  3. Giovanna Calvinisti January 5, 2011 / 9:06 PM

    Dear David: I am from Guatemala and I would like to know if you will be writing any book about descifering the Dresden Codex?

    Thank you, Giovanna

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