1881.] Notes on the Codex Troano, and Maya Chronology. 719 
NOTES ON THE CODEX TROANO, AND MAYA 
CHRONOLOGY. 
BY DANIEL G. BRINTON, M.D. 
eae investigations of Professor Thomas, published, in the 
American NaArura.ist for August, go far towards dispelling 
the obscurity which has hitherto rested on this interesting docu- 
ment. In examining its pages some other suggestions have oc- 
curred to me which may throw further light on its object and 
contents. 
One question in reference to it is, as to what precise period of 
time it refers. Up to the present there has been no opinion 
€xpressed upon this point, but I think it can be approximately if 
not definitely determined. 
To do so we must decide what was the length of an Ahau. It 
is true that all the old authors, Landa, Cogolludo, Beltran, 
Lizana and the Maya chronicler, speak of it as a period of twenty 
years; and the most recent writer on the subject, Dr. Valentini,’ 
insists on this being the proper length. On the other hand, we 
have the profound Maya scholar, Sefior Juan Pio Perez, who very 
Positively maintained that it embraced twenty-four years, only 
twenty of which, however, were counted, the remaining four be- 
ing considered “ intercalary, and, as it were, non-existent.” Al- 
though no reason whatever for this odd arrangement has been 
proffered, I am convinced that Perez is correct, and in addition to 
the valuable corroborative testimony adducel by Professor 
Thomas, I shall bring forward a calculation which some time ago 
dispelled any doubts I had on the subject. 
As the Kin Katuns, or periods of 52 years, recurred so fre- 
quently that after a few generations they could not be distinguished 
one from the other, and would thus have led to great confusion 
in chronology, the Ahau Katun was devised, embracing the much 
longer period of 312 years, and to it was referred any important 
event in history. Instead of its purpose being “ further to com- 
Plicate the calendar and to deceive the people,” as Professor 
Thomas thinks, it is, when properly used, an extremely simple 
and easy means of keeping the run of the years, and converting the 
one computation into the other.. For this purpose the series of 
Numbers was used which has been such a mystery to antiquaries: 
For 42,0, 7, 6, 4. 1. 12, 10, 5, 0 a, © 
‘The Katuns of Maya History,”’ 1880. 
