Final answer:
The Inca's history was preserved through their architecture, spiritual practices, oral traditions, and continuous cultural traditions like textile and metalwork. Iconic structures like Machu Picchu and the extensive road networks are physical testimonies of their past achievements and societal organization.
Step-by-step explanation:
The history of the Inca was preserved through various means apart from written documents. Firstly, their architecture, such as the magnificent Machu Picchu, stands as a testament to their mastery of stonework and religious dedication. These structures were often built in reverence to their gods, like Inti, the sun god, and to reflect their social structures and beliefs.
The Incas also preserved their historical legacy through their spiritual practices and worship of huacas, or sacred places within the natural landscape. Lastly, the Incas' infrastructure, like the vast road network, was an embodiment of their organizational genius and capability, linking the empire and facilitating the spread of culture.
The continuing traditions of the Andean people, such as textiles, metalwork, and ceramics, also offer insights into the Inca's past. These traditions have been passed down through generations and remain integral to the cultural heritage of the region. Moreover, oral traditions, mythologies, like the story of the Ayar brothers, and the respect for the indigenous ways among the conquered territories contributed to maintaining the Incan history alive through the ages.