CORRELATION OF MAYA AND CHRISTIAN CHRONOLOGY. 513 
The foregoing examples, even omitting the two aberrant ones, Nos. 2 and 3, 
include all five groups of month-coefficients, Eb representing the 0, 5, 10, or IS 
group; Eznab the 1, 6, 11, or 16 group; Kan, Muluc, and Ix the 2, 7, 12, and 17 
group; Ahau the 3, 8, 13, and 18 group; and Imix and possibly Cib the 4, 9, 14, and 
Ig group. 
The two examples following the New Empire usage, Nos. 2 and 3, have been 
mentioned before (see figure 75, a, and figure 74 respectively). Both, it should be 
noted, are from Uxmal, the great western Maya metropolis at the close of the New 
Empire, and both are of late date, 11.15.16.12.14 (1277 A.D.) and 11.12.17.11.1 
(1219 A. D.), that is, after the fall of Chichen Itza and the end of the League of 
Mayapan. 
While most of the other twelve are certainly earlier (Nos. 6, 7, 8, 11, and 14 
certainly so, and Nos. 5, 9, 12, and 13 probably so), at least one, No. 10 at Chichen 
Itza, the great eastern Maya metropolis of the New Empire, is surely Jater, having 
the date, I11.19.11.0.0 (1350 A. D.). 
Before analyzing these data on the monuments, let us examine the three pre- 
Columbian Maya manuscripts now known, the Codices Dresdensis, Tro-Cortesia- 
nus, and Peresianus. 
In the Codex Dresdensis the month-signs, which are scattered throughout the 
manuscript, being particularly frequent on pages 24 and 46 to 50, which deal with 
the Venus-Solar period of 2,920 days, all conform to the Old Empire usage. 
In the Codex Tro-Cortesianus only one month-sign, Cumhu, has been identi- 
fied in the Calendar Round date 13 Ahau 13 Cumhu on page 73, D, but this is sufh- 
cient to fix the system there used as the same as that in the Old Empire. 
Unfortunately, in the Codex Peresianus, the only three month-signs there 
identifiable, 16 Zac on page 4, 1 Yaxkin on page 7, and 12 Cumhu on page 18, are 
not associated with days, although it is not improbable that the first may be pre- 
ceded by an unspecified day Akbal;' if so, this codex also conforms to the Old 
Empire usage. 
A review of the foregoing archzological evidence, the monuments, and the 
codices establishes the following points: 
(1) That all the archeological evidence, save that presented on two texts alone, indicates 
that the positions of the days in the months remained unchanged throughout 
the course of Maya history, in the New Empire as well as in the Old. 
(2) That the two texts which do not agree with the above are both from the same site, 
Uxmal, and both postdate the fall of Chichen Itza and the first introduction 
of Nahua influence into Yucatan. 
(3) That in the east, at least at Chichen Itza, this shift had not taken place down to 
1350 A. D. although it is found at Uxmal more than a century earlier. 
Turning next to the post-conquest sources, the Books of Chilan Balam, it is 
evident that by the time they were written this shift of one day forward had been 
made everywhere, Ahau always having a month-coefhicient of 2, 7, 12, or 17 and 
Imix of 3, 8, 13, or 18, etc. 
The Books of Chilan Balam are so full of examples of this kind that it is only 
necessary to cite a few cases here. See the entries describing Event C in III, IV, 
and IX; six of the thirteen tun-endings in V, the Calendar Round date 11 Chuen 
18 Zac on pages 115 and 8 of the Books of Chilan Balam of Mani and Tizimin 
respectively; the Calendar Round date 5 Ahau 17 Tzec on pages 101 and 1 of the 
Books of Chilan Balam of Mani and Tizimin respectively, and others too numerous 
to require further citation. 

1This day-sign has no coefficient, but it is exactly like the column of the 13 days Akbal on page 20 of the same 
codex, and it must be regarded as Akbal if the others are. 
