Aztec and Maya Calendar
In the tonalpohualli, the sacred Aztec calendar, Monday December 10, 2012 is:
(1 -) Cuetzpalin (lizard)
1 - Calli (house)
Lord of the Night
6 - Tozoztontli (III)
(Correlation: Alfonso Caso - Nicholson's veintena alignment [adjust])
The significance of this day
Day Atl (Water) is governed by Xiuhtecuhtli, God of Fire, as its provider of tonalli (Shadow Soul) life energy. Atl is a day for purification by subjecting oneself to the ordeal of conflict. It is a good day for battle, a bad day for rest. Water brings out the scorpion, who must sting its enemies or else sting itself. Atl is the day of the holy war, which is always a battle with one's own enemies within.
The thirteen day period (trecena) that starts with day 1-Cuetzpalin (Lizard) is ruled by Itzlacoliuhqui. The 13 days of this trecena are governed by the meting out of irrational rewards and punishments. These are 13 days of confusion, a time when the noble and ignoble have equal chance to be raised up or thrown down. The warrior must be like the lizard, who is not hurt from a high fall but, instead, immediately climbs back to its perch. These are good days to keep out of sight; bad days to attract attention.
In the years after the conquest of Mexico, the xiuhpohualli (solar calendar) became tied to the Julian calendar as used by the Spaniards. This effectively introduced a leap year to the Aztec calendar every four years (this site provides the pre-conquest calendar).