Aztec culture serves as a gateway to Mesoamerican studies because it represents the connecting point between the pre-Hispanic past and the globalized present. We are able to understand Aztec culture through the accounts written in the sixteenth century by eyewitness observers, including descendents of the culture bearers, through manuscripts illustrating philosophical concepts and world views, and through archaeological studies of the material culture, including sites and settlement patterns of the Aztecs and their contemporaries.

The Aztecs created the largest state and urbanized area in pre-Hispanic Mesoamerica (Figure 1). Their continuing historical legacy is symbolized in the name of the nation and its capital, derived from the Mexica, most powerful of all Aztecs, and in the flag of the modern nation of Mexico, with its eagle-and-cactus motif capturing the moment of Tenochtitlan's establishment (Florescano 2002). Furthermore, international attention continues to focus upon the ongoing excavations at the Templo Mayor, the “Great Temple” of Tenochtitlan.

Figure 1. Map of the Aztec Empire in 1519 (after Berdan et al. 1996). Drawn by Kristin Sullivan.

Current research on the Aztecs comes from various disciplines: anthropology, history, art history, religion, and literature. Since its inception in 1990, Ancient Mesoamerica has published nearly 50 articles that encompass the branches of scholarship on the Aztecs (Table 1). The last 2008 issue of Ancient Mesoamerica opened with essays in memory of the late William Sanders (Coe 2008; Webster and Evans 2008), whose anthropological research in the Basin of Mexico introduced a generation of scholars, including us authors, to Aztec archaeology. Both articles about Sanders noted that, although he studied the cultures of the past, he thought of himself as an anthropologist first, and this anthropological perspective informed his approach to archaeological cultures. Because he strongly influenced the research programs of so many scholars and projects, the field of Aztec studies owes to Sanders a great debt of gratitude, and its various strands of endeavor—archaeology, ethnohistory, linguistics, ethnography—together have worked toward the development of a holistic view of central Mexico in the several centuries before European intrusion. We Aztec-istas have managed, in large part, to write a real ethnography of an ancient culture, and that was Bill Sanders's goal all along.

Table 1. Aztec-related topics and authors, Ancient Mesoamerica articles

Here we can only touch on major themes in recent scholarship on the Aztecs, published in Ancient Mesoamerica and elsewhere, and focus on publications from the last twenty years. Several recent books provide syntheses of Aztec art, archaeology, and ethnohistory (Aguilar-Moreno 2007; Berdan 2005; Coe and Koontz 2002:190–231; Evans 2008a:423–550; Kellog 1995; Manzanilla and López Luján 1995; M.E. Smith 2003a, 2008a; Townsend 2000; Van Tuerenhout 2005), and the European intrusion and its consequences for Aztec culture (Pohl and Robinson 2005). Important exhibitions of Aztec materials have been accompanied by studies of the culture and its masterworks (Brumfiel and Feinman 2008; Evans 2010; Levenson 1991; Matos Moctezuma and Solís Olguin 2002; Solís Olguin 2004).

FROM THE GROUND UP: ENVIRONMENT AND SUBSISTENCE

Since the time of his dissertation, Land and Water (1957; 1962), about agriculture in the Teotihuacan Valley, Sanders made clear that understanding the productive potential of the landscape was essential to an accurate perception of the culture as a whole, a concept developed by Julian Steward (1955) in his formulation of the “culture core”. The first order of information for such studies is the set of vital statistics about the land and its climate.

The Aztec heartland, the Basin of Mexico, was a challenging environment, with a base elevation of over 2,200 m asl (ca. 7,200') and a belt of alluvial plain between the boggy lakebed and the semi-arid piedmont. The Aztecs built a complicated sociopolitical structure in the Basin of Mexico because the large and dense population required for such cultural complexity was permitted by, and supported by, an impressive array of innovative cultivation systems that maximized the productivity of zones regarded as marginal. The most productive of these special methods was drained-field chinampa agriculture (Alcántara 2007; Frederick 2007; Frederick et al. 2005; McClung de Tapia 2000; McClung de Tapia et al. 2003; Nichols and Frederick 1993; Parsons 1991, 2001a; Rojas Rabiela 1993), which in the southern Basin of Mexico was critical to the growth of Tenochtitlan, the Aztec capital (Avila López 1991).

Another important specialized cultivation technique was maguey terracing, which provided a critical compliment to seed agriculture. Remnants of Aztec maguey terraces on the piedmont hill slopes of the central highlands bore Aztec house mounds and cultural remains, clearly visible until the early 1980s, when urban expansion, chisel plowing, and reforestation projects began to obliterate them. Fortunately many of these systems were documented (Evans 1990, 2000; Evans et al. 2000; Parsons 2001; Parsons and Darling 2000a, 2000b; Smith 1997; Smith et al. 1999; Smith and Price 1994). The Aztec period of agricultural land use, like previous cycles of intensification, led to environmental changes, and these have been documented for the Teotihuacan Valley and Texcoco piedmont (Córdova and Parsons 1997; McClung de Tapia et al. 2003, 2005a, 2005b).

Following the breakup of the Teotihuacan state, large settlements appeared for the first time on the lakeshore plain and lakebed, suggesting artificial drainage on a moderate to large scale. The interconnected saline lakes, Texcoco, Zumpango, and Xaltocan, were essential to the Postclassic period political economy (Parsons 2006, 2008; Parsons and Morett 2004). Surprisingly, Parsons and Morett's (2004) survey found no indications of use of the lakebed in either the Preclassic or Classic period, and this bears further study, as Lake Texcoco was important in Aztec times for hunting, fishing, bird trapping, and insect collecting, as well as salt making and transportation. The Basin of Mexico settlement pattern survey begun by Sanders in the Teotihuacan Valley laid the basis for current research on Aztec rural settlement patterns and urbanism in central Mexico (Nichols 1996; Sanders et al. 1979; Smith et al. 1999). The Aztec period occupations of the Teotihuacan Valley and the Temascalapa region to the northeast recently have been published in detail (Evans and Sanders 2000; Sanders and Evans 2000, 2001a, 2001b; Sanders and Gorenflo 2007). Computerization of the data from all the surveys has made possible new analyses of settlement and demographic patterns (Gorenflo 2006).

SETTLEMENTS AND DEMOGRAPHY

Subsistence patterns shaped settlement patterns in the Basin of Mexico and elsewhere, and as the Aztec period map in Sanders et al. (1979) showed, the Late Postclassic population occupied all habitable zones. Rural settlements tended to reflect the agricultural strategy in that the virtually continuous stretch of maguey-terraced piedmont was settled with houselot-farm plots, intermittently punctuated by loose clusters of modest civic-ceremonial architecture (Sanders and Evans 2001:969). Towns were usually located on the interface of the piedmont and alluvial plain, a pattern that reserved the alluvial plain for agriculture and often facilitated control of water sources. The large-scale conversion of Lake Chalco-Xochmilco to chinampas in the fourteenth and fifteenth centuries made them Tenochtitlan's breadbasket, but this also destroyed most of the corporate basis of southern rural chinampa villages as chinampa plots belonged to estates awarded to nobles for their allegiance (Parsons 1991).

During the Late Postclassic period, large cities once again developed in the central highlands (Charlton and Nichols 1997a). Some, such as Cholula, had persisted for centuries while others, like Tenochtitlan, were new. The great challenge for archaeologists is the overburden, which consists of the colonial and modern buildings that cover most Aztec cities and towns. Surveying and mapping operations depend on contexts revealed by construction projects, and interpretations have drawn heavily from depictions and descriptions in ethnohistorical sources. Fortunately, a comprehensive review of known Aztec material remains provides a basic source for the state of archaeological knowledge in the mid-1990s (Umberger 1996). New details of Aztec city-state life have been revealed by investigations at Azcapotzalco (García Chávez et al. 1990), Calixtahuaca (Smith, Novic, Kroefges, and Huster 2007), Chalco (Hodge 2008), Chimalhuacan Atenco (García Chávez et al. 1998), Huexotla (Brumfiel 1980), Iztapalapan (Piho Lange 1996), Otumba (Charlton et al. 2000; Evans 2001b; Nichols 1994), Xaltocan (Brumfiel 2005a, 2005d), and Yautepec (de Vega Nova 1996; Smith et al. 1994, 1999). Chiconautla was investigated decades ago by Vaillant; his research report has been updated and published, along with information from his field notes (Cohen and Elson 2008; Vaillant and Sanders 2000). Cerro Portezuelo in the eastern Basin of Mexico lost its status as a city-state capital in the Middle Postclassic period, but the Aztec occupation continued into the Early Colonial period (Garraty et al. 2008; Nichols et al. 2008).

Aztec cities and towns shared some common features: public buildings, temples, places, calmecac (school), ballcourt, and central plaza concentrated in the center (Nichols 1994; Smith 2008; Solís and Morales 1991). Markets likely were held in the main plaza, although this remains to be studied. Cities were further subdivided into neighborhoods or barrios, and an unplanned dispersed residential zone extended from the urban center.

Tenochtitlan-Tlatelolco, of course, was the dominant capital at the time of European intrusion. Archival research and excavations have revealed its distinctive size, organization, and diversity (Calnek 2003; Garduño 1997; González Rul 1996; Sanders 2003, 2008). While it was by far the largest city in Postclassic period Mesoamerica, demographic estimates for the core area of 13.7 km² (about 5.4 square miles) need to be carefully restudied. Many Aztec buildings were constructed such that rooms were at different levels and so that activities could take place on the roof, but there is no definitive evidence that they were two-story buildings. Comparison with other cities, modern and ancient, for which careful demographic estimates have been derived, yields a population estimate closer to 50,000 than to some of the higher figures commonly found in the literature (see, for example, Smith 2008a:28).

Unlike smaller cities, Tenochtitlan's central ceremonial precinct was walled, with access restricted to a few hundred or, at most, a few thousand people. Contrary to popular depictions, masses of people could not have attended the ceremonies held at the temples within the enclosed precinct (Sanders 2008). Avenues running from the city center split the city into four quarters further subdivided into large and small barrios. Some barrios were home to elite craft guilds such as goldsmiths and featherworkers. We do not know if makers of everyday goods, such as mats and pottery, also lived in their own barrios. Tenochtitlan artisans usually had workshops in their houses as they did in cities, towns, and villages throughout the empire. Most houses in the city consisted of a walled or fenced compound with buildings arranged around a patio (Calnek 2003). Along the edge of the city, house lots were small chinampa plots. Most commoners, as well as elites, owned their house lots (Sanders 2008).

The primary function of Aztec cities was political and administrative, as capitals of city-states or altepeme. Aztec rulers employed architecture and urban design to legitimize and enhance their power and position. Understanding the phenomenon of urbanization is one of the important contributions of Mesoamerican studies and was a passionate interest of Bill Sanders. His article, Tenochtitlan in 1519: A Preindustrial Megalopolis (Sanders 2008), was part of a longer-term research project that he coauthored with ethnohistorian Ed Calnek, a book about Tenochtitlan drawing on archival and archaeological investigations. The city's layout and major architecture have been studied, and its layout reflects the orthogonal planning tradition found at Teotihuacan and at Tula (M.E. Smith 2008a:142). Palaces at Tenochtitlan and elsewhere followed a plan that reflected their political heritage from Tula; each palace featured a dais room staged at a higher level and overlooking a main courtyard, which in turn opened onto the city's plaza so that the space became increasingly public (Evans 2004, 2006). This palace plan was designed as the arena for Aztec imperial government, which was a kind of participatory totalitarianism (Evans 1998, 2001a).

ECONOMY AND POLITICS

The complex relationships between economics, politics, and social structure and how rural villages and provincial cities responded to the growth of the Aztec empire, tribute systems, and increasing commerce are important ongoing research concerns (Berdan et al. 1996; P. Carrasco 1999). The rapid growth in regional population and urbanization also impacted local production and distribution systems, and migrants introduced new technologies, practices, and market preferences (Brumfiel 2005a:31).

Increasing commercialism has long been recognized as a hallmark of the Postclassic period, and market exchange expanded with the Aztec empire (Smith and Berdan 2003). The degree to which political interventions (e.g., taxation, market relocation) impeded the development of an integrated regional market network remains debatable (Blanton 1996; Nichols et al. 2002). Archaeologists have employed geochemical source analyses, mainly instrumental neutron activation analysis (INAA), of ceramics and obsidian to address these issues (Brumfiel 2005d; Charlton et al. 2008; Garcia Chavez 2004; Garraty 2006; Hodge and Neff 2005; Hodge et al. 1992, 1993; Ma 2003; Minc 1994, 2006a, 2006b; Minc et al. 1994; Neff et al. 1994, 2000; Neff and Hodge 2008; Nichols et al. 2002, 2009; Parry 2001, 2002; Skoglund et al. 2006; Smith, Burke, Hare, and Glascock 2007).

Ceramic studies have determined that Aztec pottery was made in multiple production centers, although in most cases the location of workshops is not known. During the Middle Postclassic period decorated pottery moved through a network of overlapping markets sometimes influenced by political ties and geography (García Chavez 2004; Garraty 2006; Ma 2003; Minc 2006a; Minc et al. 1994; Nichols et al. 2002, 2008, 2009). The growth of the Triple Alliance capitals of Texcoco and especially Tenochtitlan influenced the regional market hierarchy. During the Late Postclassic period, decorated pottery, notably Aztec III Black/Orange, from the Tenochtitlan production zone further penetrated market areas in the eastern Basin of Mexico and more distant regions (Charlton et al. 2008; García Márquez 2005; Garraty 2006; Hodge and Neff 2005; Minc 2006a; Nichols and Charlton 2001; Nichols et al. 2002, 2009; Ohnersorgen 2006; Skoglund et al. 2006). Lakeshore settlements such as Chiconautla enjoyed broad access to goods, while further inland in the Teotihuacan Valley, villages and towns received fewer imports (Charlton 1994; Charlton et al. 2000).

Some archaeologists see political boundaries of confederations as constraining market exchange (Hodge et al. 1992, 1993; Minc 2006a). Others argue that by the Late Postclassic period a complex interlocking market had developed in the Basin of Mexico (Blanton et al. 1993; M.E. Smith 2003a). Still others see increasing commerce and market integration but also continuing regionalism on the Basin's peripheries, as well as increased exchange between imperial capitals in hinterlands (Charlton et al. 2000; Nichols et al. 2002). Aztec imperialism's influence upon hinterland economies may have depended on whether or not a city-state capital retained its ruler and marketplace and its proximity to Tenochtitlan and Texcoco (Brumfiel 2005a:34; see also Charlton et al. 1991).

Aztec artisans manufactured everyday and luxury goods mostly from household-based workshops, and studying craft production is an active area of research. Otumba in the northeast Basin became a regional craft production center and has provided a good look at household workshops for ceramics, obsidian, ground stone, lapidary working, and maguey fiber processing (Biskowski 2000; Charlton et al. 1991, 2000; Nichols 1994; Nichols et al. 2000; Otis Charlton et al. 1993). One of its dependencies, Cihuatecpan, had a mixed economy based on obsidian biface production, maguey fiber processing, and cultivation of maguey, maize, and other crops (Evans 1996). Throughout the Aztec empire women spun and wove textiles (Brumfiel 1991; Evans 2005, 2008; McCafferty and McCafferty 1991, 2000; Nichols et al. 2000; Parsons and Parsons 1990), and this was an important source of income for the household, reinforcing gender complementarity at the household level.

Green obsidian quarried from Pachuca dominated the core blade industry in the Basin of Mexico. Skilled Aztec knappers preferred to make bifaces from gray obsidian mined at Otumba and other sources. Obsidian workshops were dispersed in Aztec cities and towns and in some rural villages (Evans 1996; Millhauser 2005; Parry 2001, 2002; Pastrana 1998, 2002; Smith, Novic, Kroefges, and Huster 2007, Spence 1985). Archaeologists have drawn on ethnography, archival sources, and experiments to better understand how obsidian tools and other goods were manufactured and how production was organized (Berdan et al., 2009; Clark 2003b; Hirth 2003b; Hirth and Andrews 2002; Parsons 2001b, 2006).

Aztec household workshops took advantage of family labor; sometimes they combined craft production and farming. Some households engaged in multicrafting of various kinds—maguey fiber workshops at Otumba both processed fibers and made spindle whorls and their molds. Household workshops employed techniques of mass production (e.g., molds for pottery vessels and figurines) to manufacture large numbers of items to meet the tribute demands of local lords and the empire, and to supply markets in towns and cities.

After the Spanish conquest Aztec artisans continued to manufacture goods such as Aztec IV Black/Orange pottery while they also adopted new technologies and adapted to demands of new consumers. Recent historical archaeology of the Aztecs or Nahuas of the Colonial period draws upon the strengths of acculturation and agency-based explanatory frameworks for understanding Nahua-Spanish colonial relations (Charlton et al. 1994, 2005; Fournier 1997; Fournier et al. 2006; Matos Moctezuma 1999, 2008; Rodriguez-Alegría 2005a, 2005b, 2007, 2008a, 2008b; Rodriguez-Alegría et al. 2003). For example, descendents of the Aztec rulers of Teotihuacan were able to expand their landholdings after the conquest and retain private holdings into the early 1800s (Sanders and Price [2003], drawing on documentary research by Guido Munch [1976]). We expect that archaeology and ethnohistory will continue to complement each other (e.g., Burkhart 1989; Kellogg 1995; Lockhart 1992), furthering our understanding of Colonial period Nahuas and their lives and society.

THEIR SOCIAL WORLD

Class stratification organized Aztec society; recent research considers how social relations and identities were defined and negotiated (Brumfiel 1998, 2000, 2005a, 2005b, 2005c, 2006; Hicks 1999; Smith 1994). Archaeologists have shown that Aztec villages were neither homogeneous nor isolated but were connected to the larger Aztec world through webs of social, political, and economic interactions. Aztec society was multiethnic and concepts of ethnicity were interwoven with connections to place (Berdan et al. 2008). Ethnicity, status, and rank were expressed through clothing (e.g., Anawalt 1990), and the production of textiles as garments and for all other uses was the specialized domain of women. In spite of being a home-based production system, textile manufacture depended on skilled labor and the artisans underwent apprenticeships lasting for years. Aztec women and gender relations emerged in the late twentieth century as important themes examined from the perspectives of gender parallelism and feminist and agency theory (Brumfiel 1991, 1996, 2001a; Evans 1998, 2008b; Joyce 2001a; Kellogg 1997; Klein 1994, 2001b; McCafferty and McCafferty 1988, 1991, 1994; Milbrath 1997).

IDEOLOGY: THE IMPORTANCE OF THE TEMPLO MAYOR

Our understanding of the ritual artifacts and settings found in archaeological investigations owes much to the many descriptions in accounts written in the Early Colonial period (Brumfiel 2001b; Elson and Smith 2001; Hassig 2001; Smith 2002). However, no Aztec archaeological site in Mexico surpasses Tenochtitlan's Templo Mayor, or “Great Temple,” for its significance in informing us about the material culture—portable and monumental—associated with ritual life and the belief system (D. Carrasco 1999; Heyden 2000a; López Luján 2005; López Luján et al. 2006; Matos Moctezuma 1990, 1994, 1997; Velázquez 2000). The excavations were famously initiated in 1978, and major publications came out in the 1980s, but work has actively continued. The site has become one of Mexico's most-visited archaeological parks, and its artifacts are among Mexico's most famous, having their own on-site museum and being sought after for exhibitions worldwide. Excavations have continued, for example, at the House of the Eagles (López Luján 2006) and the Red Temples (Olmedo 2002).

An important consequence of the discoveries at the Templo Mayor is the much clearer understanding of the design and range of variation in Aztec elite materials. So many of the “Aztec” holdings in museums around the world are unprovenienced that scholars in the past have often argued for the legitimacy of one object by comparing it with another object, which is unfortunately also lacking provenience. The impeccable contexts of Templo Mayor finds and the care taken in their recovery ushered in a new and much more secure era of perceiving the canons of Aztec style.

MASTERWORKS: THE DOCUMENTARY RECORD

Archaeologists specializing in the Aztec period may regret that so many important sites are buried beneath modern Mexico's towns and cities, but we are blessed with a wealth of documentary sources, including pictorial records and written accounts by indigenous people and by European witnesses to Aztec culture and its material remains. The last few decades have brought forth new facsimile editions and translations of major sources and have enabled a wide audience to experience the images and accounts that were, in the sixteenth century, the treasures of a privileged few.

Of all the newly available sources, two stand out: the Codex Mendoza (1992 [ca. 1541–1542]) and Durán's History of the Indies of New Spain (1994 [1581]). These two publications, with important commentaries, are a tremendous scholarly resource for understanding Aztec history and society (Figure 2). Also welcome is a new edition of Bernal Díaz del Castillo's The History of the Conquest of New Spain (2008 [1560s]). More specialized but very important are the Annals of Chimalpahin (2006 [1615]), codices such as Chimalpopoca (1992 [seventeenth century]), Cozcatzin (1994 [1572]), Telleriano-Remensis (1995 [1563]), and Tepetlaoztoc (1994 [1554]). Archaeologists have also benefited from research by our colleagues specializing in the interpretation of these sources and other documents (Boone 2000, 2007; Carrasco and Sessions 2007; Keber 1994, 2000; Mundy 1996).

Figure 2. Gold, cacao, feathers, jade, and cotton were all demanded of the tribute province of Tochtepec when it came under Aztec domination in the 1450s. Folio 46r from the Codex Mendoza shows Tochtepec's tribute requirement in these and more elaborate goods, including cloth and costumes.

THE AZTEC EMPIRE, MESOAMERICA, AND BEYOND

The Aztec empire was as much an outcome as a cause of increasing interactions—political, commercial, and ideological—that accelerated in Middle and Late Postclassic period Mesoamerica. Applying ideas from agency theory and political economy, archaeologists and ethnohistorians have looked at how relations between Tenochtitlan and conquered areas of the Gulf and Pacific coasts were contested and negotiated (Gasco 2003; Ohnersorgen 2006; Skoglund et al. 2006; Voorhies and Gasco 2005). The Aztec empire surrounded several large confederations, such as the Tlaxcallans, and shared a fortified western border with the Tarascan empire (Silverstein 2001). Although smaller in geographic extent, the more centrally organized Tarascans fielded an army that dealt the Aztecs their biggest military defeats (Pollard 2003). Despite such hostilities, goods moved across political borders within Mesoamerica and linked Mesoamerica with Lower Central America and the American Southwest, a signal of an overall increase in commerce. But interactions were not just commercial; marriage alliances, the military, and ambassadors furthered the spread of goods and practices (Boone and Smith 2003). Some archaeologists advocate a modified world systems approach to understand these developments, while others think that the modifications necessary to apply the models to pre-Hispanic Mesoamerica limits its usefulness (see articles in Smith and Berdan 2003).

FINAL THOUGHTS

All of this scholarship forms an impressive body of knowledge produced by a varied and productive tribe of Aztec scholars. We learn from and use each others' hard-won data and interpretations, appreciating the work involved in recovering any fragments of indigenous Aztec culture. We value and honor the contributions of senior scholars who have given us so much, and we regret the recent loss, from our tribe, of Bill Sanders, H.B. Nicholson, Doris Heyden, Felipe Solís, and Jaime Litvak King. Those of us who had the pleasure and privilege of knowing any of these masters of our field will remember their avidity with regard to Aztec studies. Convivial, life-affirming people, they also demonstrated the sustaining intellectual energy that results from the life of the mind, well-lived. All four would have keenly enjoyed seeing the Aztec story unfold, as new documentary sources are uncovered and given a wider audience, and as the newest finds in the field are reported.

And, of course, the great capital always fascinates. The urban tradition in the southwestern Basin of Mexico extends back for over 2,000 years, since the time of Cuicuilco, but many of us regard Tenochtitlan as the capital we seek, even as we travel around modern Mexico City. Excavations through the modern overburden, often as part of salvage projects, are revealing new details of the Aztec capital (Carballal et al. 2008; Guilliem 2008; López Wario 2007; López Wario et al. 2005; Matos Moctezuma 2008a). The discovery on the north side of the Templo Mayor of the great monolith of Tlaltecuhtli (earth deity) and new caches along with the chambers below tell us that much remains to found below the streets of Mexico City and in its archives (López Austin and López Luján 2008; Matos Moctezuma and López Luján 2007).

RESUMEN

La cultura azteca proporciona un portal a los estudios de Mesoamérica, ya que representa la coyuntura entre el pasado prehispánico y el presente globalizado. La investigación actual sobre los aztecas proviene de varias disciplinas: la antropología, la historia, la historia del arte, la religión y la literatura. Los cerca de cincuenta artículos sobre los aztecas publicados en la revista Ancient Mesoamerica, desde su creación en 1990, abarcan todas las distintas ramas de investigación sobre los aztecas. En este artículo se discuten los principales temas de los estudios recientes sobre los aztecas: el medio ambiente y la subsistencia, la colonización y la demografía, la economía, la política y las relaciones sociales, la ideología y las obras maestras, y las relaciones interregionales.