Note 35 — LECTURE III. THE SACRIFICES, SACERDOTAL AND MONASTIC INSTITUTIONS, ESCHATOLOGY AND COSMOGONY OF MEXICO.
Philip H. (Philip Henry) Wicksteed translation
The sacerdotal year was lunar. The civil year, which was doubtless of later origin, and had been adopted as better suited to the purposes of agriculture, was solar. Every thirteenth year the two coincided. The number four, which plays an important part in Mexican symbolism (cf. the Mexican cross) gave a kind of cosmic significance to 13 × 4 = 52.