Everything you thought you knew about the Aztecs is wrong. Or, as Camilla Townsend more tactfully puts it at the start of her wonderful new book: ‘The Aztecs would never recognize themselves in the picture of their world that exists in the books and movies we have made.’

The picture to which Townsend refers is perhaps best symbolised for British readers by the image on the cover of the original Angry Aztecs volume in Terry Deary’s Horrible Histories series (1997): a cartoon depicts an Aztec warrior holding a fresh human heart, saying ‘His heart was in the right place’ (covers of other editions show variations on this theme, save for a 2014 edition depicting a rat in Aztec warrior garb). The joke works because the association of the Aztecs with the practice of human sacrifice runs deep and wide: most people who know only one thing about the Aztecs know that they are famous for sacrificing people to their gods; and those who are more familiar with the Aztecs – including those who, for example, teach in schools or universities – tend to think of Aztec culture as one in which bloodthirsty rituals and exotic superstitions played central roles.

In recent decades, a growing number of scholars have pointed out the many ways and reasons why and how that perception is distorted, if not plain wrong. The Aztecs, it turns out, were no more bloodthirsty or savage than anybody else in the world – including the early modern Europeans who systematically demonised them. Their culture was part of a civilisation (that of the Nahuas of central Mexico) that was as sophisticated and accomplished as that of those Europeans who sought to destroy it.

But fighting negative stereotypes and replacing them with something less prejudicial, less sensationalist, more multifaceted and more accurate has proved to be an uphill battle. Franciscan friars in the 16th century, along with other Catholic priests and chroniclers, created a portrait of Aztec religion, politics and social practices that was designed to justify the often-violent imposition of Spanish colonisation and forced conversion to Christianity. That portrait took root and flourished for centuries. The era of the global triumph of European empires was fertile ground for derogatory views of ‘barbarian’ societies swept aside by civilisation’s progress. When new fields of study and new evidence on the Aztec past emerged – archaeological discoveries from beneath Mexico City, for example, or unpublished manuscripts written in Nahuatl in the early colonial period – they tended to be deployed to confirm, or at best modify, that deep-rooted stereotype, not upend it.

What has changed? As Townsend explains in an appendix to Fifth Sun, not until the 21st century was there a convergence of scholars with a profound grasp of colonial-era Nahuatl, a willingness to challenge the well-established portrait of the Aztecs on which generations of scholars had built their careers and a readily available body of sources written in the early colonial decades by the descendants of the Aztecs (mostly in Nahuatl). Townsend makes particular use of a genre of documentation called xiuhpohualli by its Nahua writers. Literally meaning ‘yearly account’, such sources were more like community histories. Townsend presented the xiuhpohualli in greater detail in an earlier book, Annals of Native America (2016), so here they stand as the largely invisible foundation to her reconstruction of Aztec history. But, significantly, they allow her to present the Aztec past through a skilful synthesis of Nahua memories and traditions. From start to finish – even after Spaniards appear on the scene – the perspective is Aztec-centric to an unprecedented degree.

The bulk of the book is devoted to the two centuries that straddled the Spanish invasion that began in 1519. Its narrative thus takes off in the 1420s, as the Mexica rulers forge the alliance of city-states that we call the Aztec Empire. The story’s basic elements are common to human history and are therefore broadly familiar: the leaders of a marginalised town turn the tables on the neighbours who have dominated them, generating a momentum of expansion that within a generation or so turns that town into the capital city of a diverse empire. Such a tale can be gripping and, in Townsend’s hands, it is certainly that.

Despite the dramatic changes that resulted from the Spanish invasion, Townsend is able to maintain an Aztec-centric (or, after the fall of the Aztec Empire, Nahua-centric) perspective into the 17th century. Considering that even her most important source documents – such as the xiuhpohualli – were written alphabetically by Christians, some with partial Spanish ancestry, that is no small accomplishment. The final 80 pages of Fifth Sun offer one of the best descriptions of the first century of Mexico’s colonial period I have ever read. In fact, this is the best book on the Aztecs yet written, full stop.

That is not just because of its focus on the Aztec perspective and not just because Nahua history is presented through Nahua sources and in terms that are sensitive and sensible to indigenous culture. Townsend has not set out to pen an Aztec apologia. She shies away from polemical defences of Aztec practices and from romanticising the individual Nahuas who play central roles in her telling of their history –although, to be fair, she comes close to an intellectual romance with Nahua women surviving the conquest wars (such as Moctezuma’s daughter, Tecuichpotzin, and Cortés’ interpreter, Malintzin) and with some of the xiuhpohualli authors.

Rather, the value of Fifth Sun lies in how it rescues Aztecs and Nahuas from centuries of colonialist caricature and renders them human again – fully human, with flaws, people capable of brutal violence but also of deep love, who also savoured ‘a good laugh, just as we do’. We are so ‘accustomed to being afraid of the Aztecs, even to being repulsed by them’, that it has never occurred to us that we might simply identify with them. With this book, that can change.