From Seven Myths of the Spanish Conquest, by Matthew Restall (Oxford, 2004), Kindle Loc. 443-474:
The Mexican historian Enrique Florescano has observed that the Conquest gave rise to “a new protagonist of historical action and narration: the conquistador” and with him “a new historical discourse” that featured “a new manner of seeing and representing the past.” The historical discourse of the conquistadors may have been new in the sense of its application to the Americas, but it was actually based on a genre of document developed by Iberians before they reached the New World [during the Reconquista]. This genre was the report that conquerors sent to the crown upon completion of their activities of exploration, conquest, and settlement. Such reports had a dual purpose. One purpose was to inform the monarch of events and newly acquired lands, especially if those lands contained the two elements most sought as the basis for colonization—settled native populations, and precious metals. The other purpose was to petition for rewards in the form of offices, titles, and pensions. Hence the Spanish name for the genre, probanza de mérito (proof of merit).
The very nature and purpose of probanzas obliged those who wrote them to promote their own deeds and downplay or ignore those of others—to eliminate process and pattern in favor or individual action and achievement. Most of Conquest mythology can be found in these reports—the Spaniards as superior beings blessed by divine providence, the invisibility of Africans and native allies, the Conquest’s rapid rush to completion, and above all the Conquest as the accomplishment of bold and self-sacrificing individuals.
Probanzas are also important because so many were written. Literally thousands sit in the great imperial archives in Seville, and still more are in Madrid, Mexico City, Lima, and elsewhere…. Most such reports were brief—a page or two—wooden, formulaic in style, given scant attention by royal officials, then shelved until their rediscovery by twentieth-century historians. Many, no doubt, have never been read. But an influential minority were widely read either through publication as conquest accounts, or by being worked into colonial-period histories. For example, the famous letters by Cortés to the king, which were in effect a series of probanzas, were published shortly after reaching Spain. They so efficiently promoted the Conquest as Cortés’s achievement, and sold so well in at least five languages, that the crown banned the cartas lest the conqueror’s cult status become a political threat. The letters continued to circulate, however, and later admirers traveled like pilgrims to Cortés’s residence in Spain. The Cortés cult was further stimulated by Gómara’s hagiography of 1552—that the crown attempted to suppress too.
There was plenty of precedent to the publication of probanza-like letters and to crown intervention in their distribution or suppression. Within months of Columbus’s return to Spain from his first Atlantic crossing, a “letter” putatively written by him but actually crafted by royal officials based on a document by Columbus was published in Spanish, Italian (prose and verse versions), and Latin. It promoted the “discovery” as a Spanish achievement that cast favorable light on the Spanish monarchs and on Columbus as their agent. Significantly, it also made the letter originally written by Columbus, who as a Genoese would have been less familiar with the Iberian genres, look more like a Spanish probanza.