Azcapotzalco (altepetl) in the context of "Aztec Empire"

The Aztecs (/ˈæztɛks/ AZ-teks) were a Mesoamerican civilization that flourished in central Mexico from 1300 to 1521. The Aztec people included different ethnic groups of central Mexico, particularly those groups who spoke the Nahuatl language. Aztec culture was organized into city-states (altepetl), some of which joined to form alliances, political confederations, or empires. The Aztec Empire was a confederation of three city-states established in 1427: Tenochtitlan (the capital city of the Mexica or Tenochca), Tetzcoco, and Tlacopan, previously part of the Tepanec empire, whose dominant power was Azcapotzalco. Although the term Aztecs is often narrowly restricted to the Mexica of Tenochtitlan, it is also broadly used to refer to Nahua polities or peoples of central Mexico in the prehispanic era, as well as the Spanish colonial era (1521–1821).

Most ethnic groups of central Mexico in the post-classic period shared essential cultural traits of Mesoamerica. The culture of central Mexico includes maize cultivation, the social division between nobility (pipiltin) and commoners (macehualtin), a pantheon, and the calendric system. Particular to the Mexica of Tenochtitlan was the patron god Huitzilopochtli, twin pyramids, and the ceramic styles known as Aztec I to IV. The Mexica were late-comers to the Valley of Mexico, and founded the city-state of Tenochtitlan on unpromising islets in Lake Texcoco, later becoming the dominant power of the Aztec Triple Alliance or Aztec Empire which conquered other city-states throughout Mesoamerica. It originated in 1427 as an alliance between the city-states Tenochtitlan, Texcoco, and Tlacopan to defeat the Tepanec state of Azcapotzalco, which had previously dominated the Basin of Mexico. Soon Texcoco and Tlacopan were relegated to junior partnership in the alliance, with Tenochtitlan the dominant power. The empire extended its reach by a combination of trade and military conquest. It was never a true territorial empire controlling territory by large military garrisons in conquered provinces but rather dominated its client city-states primarily by installing friendly rulers in conquered territories, constructing marriage alliances between the ruling dynasties, and extending an imperial ideology to its client city-states. Client city-states paid taxes, not tribute to the Aztec emperor, the Huey Tlatoani, in an economic strategy limiting communication and trade between outlying polities, making them dependent on the imperial center for the acquisition of luxury goods. The political clout of the empire reached far south into Mesoamerica conquering polities as far south as Chiapas and Guatemala and spanning Mesoamerica from the Pacific to the Atlantic oceans.

The Aztec Empire, also known as the Triple Alliance (Classical Nahuatl: Ēxcān Tlahtōlōyān, [ˈjéːʃkaːn̥ t͡ɬaʔtoːˈlóːjaːn̥]) or historiographically as the Tenochca Empire, was an alliance of three Nahua city-states: Mexico-Tenochtitlan, Tetzcoco, and Tlacopan. These three city-states ruled that area in and around the Valley of Mexico from 1428 until the combined forces of the Spanish conquistadores and their native allies who ruled under Hernán Cortés defeated them in 1521. Its people and civil society are historiographically referred to as the Aztecs or the Culhua-Mexica.

The alliance was formed from the victorious factions of a civil war fought between the city of Azcapotzalco and its former tributary provinces. Despite the initial conception of the empire as an alliance of three self-governed city-states, the capital Tenochtitlan became dominant militarily. By the time the Spanish arrived in 1519, the lands of the alliance were effectively ruled from Tenochtitlan, while other partners of the alliance had taken subsidiary roles.

The Acolhua are a Mesoamerican people who arrived in the Valley of Mexico in or around the year 1200 CE. The Acolhua were a sister culture of the Aztecs (or Mexica) as well as the Tepanec, Chalca, Xochimilca and others.

The most important political entity in ancient Mesoamerica was the Triple Alliance (Nahuatl, excan tlatoloyan), founded in 1428 when the rulers of Tenochtitlan, Texcoco, and Tlacopan formed an alliance that replaced the Tepanec Empire of Azcapotzalco and eventually integrated into a single polity the most developed regions of western Mesoamerica. Because of the predominance of Tenochtitlan, it has also been called the Mexica, Aztec, or Tenochca Empire. It came to an end with the Spanish conquest of 1521.

Tacuba is a section of northwest Mexico City. It sits on the site of ancient Tlacopan. Tacuba was an autonomous municipality until 1928, when it was incorporated into the Central Department along with the municipalities of Mexico, Tacubaya and Mixcoac. The Central Department was later divided into boroughs (delegaciones); historical Tacuba is now in the borough of Miguel Hidalgo. The area was designated as a "Barrio Mágico" by the city in 2011.

Tacuba was called Tlacopan in the pre-Hispanic period. Tacuba is derived from the former Nahuatl name "Tlacopan" and means place of the jarilla plant. It was conquered by Azcapotzalco which placed Totoquihuatzin as governor. When the Tenochtitlan and Texcoco decided to ally against Azcapotzalco, Tlacopan did not resist and for this reason is considered to be the third of the Aztec Triple Alliance. Tacuba's importance led to the construction of a causeway over the lake linking it with Tenochtitlan. Today, this causeway still exists as a major thoroughfare called Calzada Mexico-Tacuba.