Eleven glyph blocks painted in an inverted L on a wall in northern Guatemala end with a personal name: Sak Tahn Waax, which the researchers translate as “White-chested Fox” in their reading of the signature. The inscription, known as Text 19, records an astronomical calculation spanning 2,920 days, and its closing signature makes the author the first Classic Maya mathematician known to be credited by name for his own work.
Text 19 on the wall of Structure 10K-2
The text sits on an interior wall of Structure 10K-2 at Xultun, in the Petén region of Guatemala. The authors of the new study call Text 19 a microtext, and unlike the calculations around it, this one ends by naming who stands behind it, which is the feature that sets it apart in their account.
The reconstruction and transcription come from Franco D. Rossi of the Massachusetts Institute of Technology, David Stuart of the University of Texas at Austin and Heather Hurst of Skidmore College. Their paper, “The identification and work of an eighth-century Maya mathematician,” appears in Antiquity, volume 100, issue 413, pages 1369 to 1384, and was first published online on 14 July 2026. Its DOI is 10.15184/aqy.2026.10378. The article states that Text 19 “comprises 11 glyph blocks arranged in an inverted ‘L’,” and that the first nine form the calculation while the last two form the attribution. Archaeologists found the chamber in 2010, and Arkeonews reports that it holds about 52 texts on astronomy, lunar cycles and numerical calculations, with new information still emerging sixteen years after the discovery.
That attribution is “a clear personal name, spelled SAK-TAHN-wa-xi,” introduced by the quotative cheheen, which the authors render as “so says.” They suggest it may be the author’s signature. In the abstract they put the significance bluntly: “this is the only known example of a Classic Maya mathematician directly credited for their work.” Arkeonews phrases the same finding as the first known Classic Maya mathematician to receive direct credit for his intellectual work.
A 2,920-day span that fits Venus and the sun
The calculation is built from four intervals of 20, 260, 1,560 and 1,080 days, which add up to the 2,920-day total the paper reports. The number is not arbitrary. The authors describe 2,920 as the lowest common multiple of the Venus synodic period of 584 days and the 365-day solar year, so it equals five Venus cycles and also eight solar years.
The 1,560-day interval, according to the paper, equals two cycles of Mars, taking a Mars cycle as 780 days. The 1,080-day interval is three periods of 360 days, the Maya “year” of the count. Arkeonews adds that the specific arrangement of the 20-day month, the 260-day ritual calendar, the 360-day count and the roughly 780-day Mars cycle is not found in other Maya texts, so the wall preserves a combination of cycles that no other known inscription repeats. The Venus figure of 584 days and the solar year of 365 days complete the set of four astronomical quantities the author had to keep in step.
Reconstructed calendar signs give a starting date of 9.17.10.17.3, 4 Akbal 6 Muan, which Arkeonews converts to November 11, AD 781 in the Gregorian calendar. The report is careful to call that a possible starting point for the calculation rather than the day the paint dried.
The Fibonacci twist, and what it does not prove
The detail that has travelled furthest is the resemblance to the Fibonacci sequence. Counted in units, the calculation uses one 20-day month and one 260-day cycle, then two Mars cycles, three 360-day periods and five Venus cycles: 1, 1, 2, 3 and 5. The authors write that “these intervals follow what is known as a Fibonacci sequence in western mathematics.” Reporting on the study extends the run to eight, the number of solar years the same 2,920 days contain, so the whole calculation can be read as a progression of 1, 1, 2, 3, 5 and 8.
The authors do not claim more than that. They say it is unknown how far Maya mathematicians understood such a pattern, and Arkeonews states that the Xultun author did not discover the sequence in the modern sense. The intervals themselves, listed in days as 20, 260, 1,560 and 1,080, do not rise in Fibonacci order, so the resemblance lives in the counts of cycles, not in the day totals. Whether it was deliberate is an open question the paper leaves standing.
A second caution concerns the word “his.” Arkeonews notes that a name at the end of a formula does not necessarily mean its bearer personally calculated or painted it; another scribe may have recorded his work. The credit is real, but the exact relationship between Sak Tahn Waax and the paint on the wall is not settled by the glyphs alone.
Where the finding has been reported
The result drew coverage soon after the July publication. Phys.org ran a piece headlined “Hidden in Maya wall writings: A named astronomer emerges from 1,200-year-old calculations”, and the journal’s own site carries a news item on the discovery. Arkeonews followed on 10 October 2026 with the fullest plain-language account of the numbers.
The paper’s own wording, “the only known example,” is a statement about the surviving record rather than about every scribe who ever worked. Among the roughly 52 texts Arkeonews counts in the chamber, Text 19 is the one the authors identify as signed, and whether any other wall or codex preserves a comparable credit is a question the published study does not answer.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
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