How did Spanish accounts and archaeology help historians study the Inca despite the lack of alphabetic writing?

Despite the lack of alphabetic writing, historians have reconstructed the history of the Inca through a combination of archaeological evidence, oral tradition, and colonial-era documentation.12

The Role of Quipus

The Inca maintained detailed records using the quipu, an apparatus of knotted cords. While these were primarily used by professional accountants for quantitative data—such as tracking populations, livestock, and commodities—they also served as historical records. Modern researchers have studied specific quipus, such as those kept by Don Francisco Cusichaq, to identify historical sequences of events, though the non-quantitative aspects of these records remain largely undeciphered.312

Spanish Accounts and Ethnography

Following the conquest, Spanish observers transcribed oral histories provided by the Inca. In 1549 and the 1570s, systematic investigations were conducted to document the Andean past. Notable figures included:12
* Pedro de Cieza de León: A soldier and interviewer who cross-referenced oral traditions from different royal lineages to ensure accuracy.1
* Garcilaso de la Vega: The son of an Inca royal woman, whose The Royal Commentaries of the Inca became a primary source for colonial-era understanding.1
* Guamán Poma de Ayala: An Andean writer whose 1,200-page letter to the Spanish king included 400 pages of drawings that provide critical insights into Inca society.1