The four signs which alone might commence the year—acatl (reed), tecpatl (flint), calli (house), tochtli (rabbit), took the numbers 1 to 13 continuously. The numbering of the years thus provided that every one of the 52 years of the xiuhmolpilli (or Calendar Round) was distinguished from every other. The whole cycle of 52 years was thus divided into four quarters of 13 years each. These year-names were each referred to a particular quarter of the heavens, the acatl years to the east, tecpatl to the north, calli to the west, and tochtli to the south. The computation began in the east with the acatl years, strangely enough with 2 acatl, the cycle thus closing with 1 tochtli. The Aztecs believed that the current epoch had begun with the year 1 tochtli, for it was in this period that the world had undergone reconstruction. Not until this was completed could the first cycle of 52 years be begun. Therefore 2 acatl is the opening year of the first and of all following cycles, and is usually represented by the picture of a fire-drill. The years had also colours and patron gods of their own as follows: acatl—yellow (gods Tonatiuh and Itztli); tecpatl—red (god Mictlantecutli); calli—blue (earth-goddesses); tochtli—white (Tlaloc). Arranged in tabular form, this would appear as follows: Year-name Direction Colour Patron God Acatl East Yellow Tonatiuh and Itztli Tecpatl North Red Mictlantecutli Calli West Blue Earth-goddesses Tochtli South White Tlaloc THE NEMONTEMI