The Aztec Empire 

The Aztec Empire is not completely analogous to the empires of European history. Like most European empires, it was ethnically very diverse, but unlike most European empires, it was more a system of tribute than a single system of government. Arnold Toynbee in War and Civilization analogizes it to the Assyrian Empire in this respect. 

Although cities under Aztec rule seem to have paid heavy tributes, excavations in the Aztec-ruled provinces show a steady increase in the welfare of common people after they were conquered. This probably was due to an increase of trade, thanks to better roads and communications, and the tributes were extracted from a broad base. Only the upper classes seem to have suffered economically, and only at first. There appears to have been trade even in things that could be produced locally: love of novelty may have been a factor. 

The most important official of Tenochtitlan government is often called The Aztec Emperor. The Nahuatl title, Huey Tlatoani (plural huey tlatoque), translates roughly as "Great Speaker"; the tlatoque ("speakers") were an upper class. This office gradually took on more power with the rise of Tenochtitlan. By the time of Auitzotl "Emperor" is an appropriate analogy, although as in the Holy Roman Empire, the title was not hereditary. 

Most of the Aztec empire was forged by one man, Tlacaelel (Nahuatl for "manly heart"), who lived from 1397 to 1487. Although he was offered the opportunity to be tlatoani, he preferred to stay behind the throne. Nephew of Tlatoani Itzcoatl, and brother of Chimalpopoca and Motecuhzoma I Ilhuicamina, his title was "Cihuacoatl" (in honor of the goddess, roughly "counselor"), but as reported in the Ramírez Codex, "what Tlacaellel ordered, was as soon done". He gave the Aztec government a new structure, he ordered the burning of most Aztec books (his explanation being that they were full of lies) and he rewrote their history. In addition, Tlacaelel reformed Aztec religion, by putting the tribal god Huitzilopochtli at the same level as the old Nahua gods Tlaloc, Tezcatlipoca, and Quetzalcoatl. Tlacaelel thus created a common awareness of history for the Aztecs. He also created the institution of ritual war (the flower wars) as a way to have trained warriors, and created the necessity of constant sacrifices to keep the Sun moving. Some writers believe upper classes were aware of this forgery, which would explain the later actions of Moctezuma when he met Hernán Cortés (a.k.a. Cortez). But eventually this institution helped to cause the fall of the Aztec empire. The people of Tlaxcalla were spared conquest, at the price of participating in the flower wars. When Cortés came to know this, he approached them and they became his allies. The Tlaxcaltecas provided thousands of men to support the few hundred Spaniards. The Aztec strategy of war was based on the capture of prisoners by individual warriors, not on working as a group to kill the enemy in battle. By the time the Aztecs came to recognize what warfare meant in European terms, it was too late.