The Aztec Empire, which was at its peak between 1345 and 1521CE, was comprised of a series of city states which were known as altepetl. For the sake of reference, a city state is defined as a city that becomes an independent state or country. Modern-day examples of city states include Singapore, Monaco, and Vatican City.

Getting back to the altepetl, each one was led by a tlatoani, or supreme leader, and a cihuacoatl, or administrator. The tlatoani of the capital city of Tenochtitlan(modern-day Mexico City) was the huey tlatoani, or emperor, of the entire Aztec empire.

In each altepetl, the tlatoani was the owner of all land. It was his responsibility to resolve judicial disputes, lead the army, and oversee the markets.

As his second-in-command, the cihuacoatl handled the financial affairs of the altepetl and was the supreme judge in the judicial system.

The government structure of the Aztecs was based on the family unit. Multiple family units owned land collectively, and these groupings were known as calpulli. The calpulli was around long before the Aztec empire and included a local governing council who were responsible for maintain schools and collecting taxes.

The calpulli that grew into cities like Tenochtitlan became more influential and larger. They in turn elected an executive council which contained a tlacani, or singular leader who would control the city and the surrounding lands.

The leader of the city of Tenochtitlan became known as the Huey Tlatcani, or Great Speaker, also known as the emperor. He was worshipped as a god and supported by the priests and warriors. He could be removed from power since he was technically elected through the tlancani system, but this was rarely done.