It is common for students to think that the events which unfolded after 1519 represented a contest between the "Aztecs" and the Spaniards. One should explain to the students that the people who lived in central Mexico in 1519 did not call themselves the "Aztecs." The group that ruled from Tenochitlán called themselves the Mexicas. The Mexicas spoke Nahuatl and shared common cultural and religious beliefs with other Nahuatl-speaking indigenous people living in Mexico. Though many of the other Nahuatl-speaking peoples hated the Mexicas, it was not because of fundamentally different ways of viewing the world. Most of these other peoples worshipped the same gods and, like the Mexicas, practiced human sacrifice. How then does one explain how Cortés acquired his Amerindian allies? To answer this question, one needs to look at the circumstances surrounding the rise of the Mexicas.

Unfortunately, most semester-based courses (and textbooks) break at 1500. This means that they rarely include any background information that will help students understand the hostility toward the Mexicas. Coupled with the lack of attention to this topic in earlier volumes, this problem means that it is unlikely that students will have the background to understand the complex politics of pre-colonial Mexico that so shaped the conquest itself. For this reason, I have included a limited amount of information on the rise of the Mexicas here. For further reading, consult the annotated bibliography.

The Mexicas claimed to descend from the Toltecs, a military power that established its capital in the city of Tula after the collapse of the classic Mayan civilization around 750 C.E. With the demise of the Toltecs's authority, Mexico broke up into city states. Some of these city states were defined by the languages spoken: Otomi, Tarascan, Totonac, and Nahuatl, but there were many differences and conflicts between the Nahuas as well. Most of the major city states were concentrated around the banks of Lake Texcoco, in central Mexico. Lacking any central authority, these city states were often at war with one another.

Sometime around 1250 CE, a group of Nahuatl speaking people, the Mexicas, from northern Mexico migrated south, according to legend following their god Huitzilopochtli. The lake populations despised and discriminated against the migrants, who eventually settled on some islands in the middle of the lake, where they constructed the cities of Tenochtitlan and Tlatelolco. By the early fifteenth century, the Mexicas began to expand their power, especially under the leadership of Itzcoatl (1426-1440) and Moctezuma I (1440-1468), grandfather of Moctezuma Xoycotl (II). By the death of Moctezuma I in 1468, the Mexicas controlled most of Central Mexico. They also controlled some other peoples, like the Totonacs, as well. Significantly, important groups resisted Mexicas control and remained independent. These peoples included the Tarascans, who lived north of Lake Texcoco, and the cities of Tlaxcala, Huexotzinco, and Metzitlán, located east of the lake. The Tlaxcalans became especially important allies of the Spaniards as Cortés marched east from the Gulf Coast to Tenochtitlan.

To summarize: at the time of the conquest, the Mexicas, with their capital in Tenochtitlan was allied with the other lake city, Tlatelolco, and the lakeside cities of Texcoco and Tlacopan. At the same time, though many of their leaders had ambivalent attitudes towards the Spaniards, the city states of Tlaxcala, Huexotzinco, and Metzitlán were potential allies when the Spaniards arrived.

One still has the question, why the hostility? Many of the native populations in the Valley of Mexico resented the Mexicas from the moment 10,000 of them arrived. The Mexicas, no matter how much they attempted to tie themselves to the Toltecs, never really succeeded in forging any sense of legitimacy about their rule. Most native populations did not believe they belonged there, which reduced the Mexicas to ruling by force alone. Moreover, living in a complex urban civilization in a city constructed in the middle of a lake did not provide the Mexicas with self-sufficiency in food. They were dependent on food from outside sources, which they acquired through forced taxation (requiring tribute). Most city states resented the tribute. If this were not enough, as the city grew and modernized, the Mexicas required slaves for complex building projects. Slaves constructed most of the wonders of the city that awed the Spaniards. Finally, if one can believe the accounts, the Mexicas practiced human sacrifice on a regular basis. Most resented was the fact that the Mexicas sacrificed victims to Huitzilopochtli, the patron god of the Mexicas, the god responsible, according to the legend, for bringing the Mexicas to central Mexico in the first place. According to one reputable historian, Inga Clendinnen, the Mexicas essentially annihilated the Huaxtec population after they unsuccessfully revolted against the Mexicas in 1487. Clendinnen estimates that as many as twenty thousand people were sacrificed in four days. All of this is a long way of arguing that it is wrong to interpret the conquest of Mexico as simply a contest between the Mexicas and the Spaniards, for many indigenous peoples had legitimate reasons for seeing the Spaniards as potential liberators. Many of these same peoples may have regretted their decision later, when Spanish abuses rivaled those of the Mexicas's, but the historian's job is to try to understand why these peoples behaved the way they did at the time.