In the colonial history of Latin America, The Conquest of New Spain is a vivid, military account that establishes Bernal Díaz del Castillo "among chroniclers what Daniel Defoe is among novelists". Late in life, when Díaz del Castillo was eighty-four years old, and residing in his encomienda estates in Guatemala, he wrote The True History of the Conquest of New Spain to defend the story of the common-soldier conquistador within the histories about the Spanish conquest of Mexico. He presents his narrative as an alternative to the critical writings of Fr. Bartolomé de Las Casas, whose Indian-native histories emphasized the cruelty of the conquest; and the histories of the hagiographic biographers of Hernán Cortés - specifically that of Francisco López de Gómara, whom he believed minimized the role of the 700 enlisted soldiers who were instrumental to conquering the Aztec empire.
That said historians and hagiographers speak the truth "neither in the beginning, nor the middle, nor the end", is why Díaz del Castillo strongly defended the actions of the conquistadors, whilst emphasising their humanity and honesty in his eyewitness narrative, which he summarised as: "We went there to serve God, and also to get rich".
The history is occasionally uncharitable about Captain Cortés, because, like other professional soldiers who participated in the Conquest of New Spain, Díaz del Castillo found himself among the ruins of Tenochtitlán only slightly wealthier than when he arrived to Mexico; a financial state common to many soldiers, who accused Cortés of taking more loot than his agreed fifth of the Aztec treasury.
Certainly, the land and gold compensation paid to many of the conquistadores proved a poor return for their investment of months of soldiering and fighting across Mexico and the Anahuac Valley. Another interpretation of The Conquest of New Spain proposes that the author was one of several family relatives of Diego Velázquez de Cuéllar, the governor of Cuba, and mortal enemy of Cortés; many of whom later plotted against the conquistador Captain. Although the narrative thrust diminishes the Cortés-Díaz del Castillo relationship, contrary to the factual record, his complex relationship with Cortés, and the sub-ordinate captains, suggests that, although he represented the faction of Governor Velázquez de Cuéllar in the expedition, Bernal Díaz del Castillo fully honoured his personal and military loyalty to Hernán Cortés.