The Aztec throne did not pass automatically from father to eldest son, an element of selection was involved (although the number of potential candidates was limited). A council of warriors, priests and various officials selected the succeeding king from the members of the royal family, and military leadership and priestly aptitude were perhaps the most important criteria.

The Aztec culture was structured to refine the art of warfare, the means by which they had conquered and dominated in a world of conflicting states. The king was an important part of this process, and his success or otherwise was judged on his military victories and his ability to deliver captives for sacrifice to the ever-hungry gods. Soon after ascending the throne, a new king was expected to lead his troops on a campaign of conquest, the success of which was a vital test of his worth.

Tizoc (ruled 1481-86) returned from one such mission with only 40 captives and the loss of 300 of his own men: his reputation never recovered and his reign was to last only five years. According to the chroniclers, "members of his court, angered by his weakness and his lack of desire to bring glory to the Aztec nation, helped him to die with something they gave him to eat..." Ironically enough Tizoc is best known for the massive monument called the Stone of Tizoc (now in the National Museum of Archaeology in Mexico City), whose carvings depict a series of Aztec triumphs... only one of which can be linked to Tizoc's known campaigns and the rest presumably celebrating the empire he inherited rather than his own meagre achievements!