Tlacopan 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.

Tlahtoāni (Classical Nahuatl: tlahtoāni pronounced [t͡ɬaʔtoˈaːniˀ] , "ruler, sovereign"; plural tlahtohqueh [t͡ɬaʔˈtoʔkeʔ]) is a historical title used by the dynastic rulers of āltepēmeh (singular āltepētl, often translated into English as "city-state"), autonomous political entities formed by many pre-Columbian Nahuatl-speaking peoples in the Valley of Mexico during the Postclassic Period. The title of huēyi tlahtoāni [es] ([ˈweːjiˀ t͡ɬaʔtoˈaːniˀ], "great ruler, emperor") was used by the rulers of the Aztec Empire, an alliance between the āltepēmeh of Tenochtitlan, Tetzcoco, and Tlacopan.

Each āltepētl had its own tlahtoāni who would concurrently function as its ruler, high priest and commander-in-chief. The tlahtoāni wielded ultimate authority over all land within the āltepētl, overseeing tribute collection, market activities, temple affairs, and the resolution of judicial disputes. Typically a dynastic ruler hailing from the royal lineage, the tlahtoāni served for life. However, in certain instances, a council of nobles, elders, and priests could elect a tlahtoāni from a pool of four candidates.

The altepetl (Classical Nahuatl: āltepētl [aːɬ.ˈte.peːt͡ɬ] , plural altepeme or altepemeh [aːɬ.ˈte.ˈpeːme(h)]) was the local, ethnically-based political entity, usually translated into English as "city-state", of pre-Columbian Nahuatl-speaking societies in the Americas. The altepetl was composed of smaller units known as calpolli and was typically led by a single dynastic ruler known as a tlatoani, although examples of shared rule between up to five rulers are known. Each altepetl had its own jurisdiction, origin story, and served as the center of Indigenous identity. Residents referred to themselves by the name of their altepetl rather than, for instance, as "Mexicas". "Altepetl" was a polyvalent term rooting the social and political order in the creative powers of a sacred mountain that contained the ancestors, seeds and life-giving forces of the community. The word is a combination of the Nahuatl words ātl (meaning "water") and tepētl (meaning "mountain"). A characteristic Nahua mode was to imagine the totality of the people of a region or of the world as a collection of altepetl units and to speak of them on those terms. The concept is comparable to Maya cah and Mixtec ñuu. Altepeme formed a vast complex network which predated and outlasted larger empires, such as the Aztec and Tarascan state.

Established altepeme were characterized by a central temple dedicated to a patron god particular to the identity of the altepetl and a central market. Altepeme were typically multiethnic and communal cohesion was often maintained through territorial exclusiveness.

Aztec warfare concerns the aspects associated with the military conventions, forces, weaponry and strategic expansions conducted by the Late Postclassic Aztec civilizations of Mesoamerica, including particularly the military history of the Aztec Triple Alliance involving the city-states of Tenochtitlan, Texcoco, Tlacopan and other allied polities of the central Mexican region. This united the Mexica, Apulteca, and Chichimeca people through marriages.

The Aztec armed forces were typically made up of a large number of commoners (yāōquīzqueh [jaː.oːˈkiːskeʔ], "those who have gone to war") who possessed extensive military training, and a smaller but still considerable number of highly professional warriors belonging to the nobility (pīpiltin [piːˈpiɬtin]) and who were organized into warrior societies and ranked according to their achievements. The Aztec state's primary purpose was political expansion and dominance of and exaction of tribute from other city-states, a purpose that relied on constant warfare. Aztec society was also centered on warfare: every Aztec male received basic military training from an early age and one of the few possible opportunities of upward social mobility for commoners (mācehualtin [maːseˈwaɬtin]) was through military achievement, especially the taking of captives (māltin [ˈmaːɬtin], singular malli). Thus only specifically chosen men served in the military. The sacrifice of war captives was an important part of many of the Aztec religious festivals. Warfare was thus the main driving force of both Aztec economy and religion.