Mayan Politics
In both the priesthood and the ruling class, nepotism was apparently the prevailing system under which new members were chosen. Primogeniture was the form under which new kings were chosen as the king passed down his position to his son. After the birth of a heir, the kings performed a blood sacrifice by drawing blood from his own body as an offering to his ancestors. A human sacrifice was then offered at the time of a new king's installation in office.
To be a king, one must have taken a captive in a war and that person is then used as the victim in his accession ceremony. This ritual is the most important of a king's life as it is the point at which he inherits the position as head of the lineage and leader of the city. The religious explanation that upheld the institution of kingship asserted that Maya rulers were necessary for continuance of the Universe.
The Maya kings timed their accession rituals in tune with the stars and the Milky Way. They celebrated k'atun endings approximately every twenty years. At the end of the 20-year k'atun period, Maya rulers regularly erected a stela, called a stone tree, to commemorate the event. On stone stela they depicted themselves at the time of these ceremonies dressed in costumes that contained the symbols that were associated with the World Tree. Their headdresses contained the Principal Bird Deity, in their arms they held a so-called ceremonial bar that represented the double-headed serpent of the ecliptic. By wearing the costume elements of the World Tree the Maya ruler linked himself to the sky, the gods and that essential ingredient, life.
In addition, it has been found that when the k'atun ending coincided with certain planetary positions the Maya went to war to obtain captives. The cosmology of the Maya was a living, religious philosophy that permeated their lives to a degree that might seem excessive to modern people. They were astute observers, sensitive to the cyclical nature of the sun, moon and planets.