Quechua had already expanded across wide ranges of the central Andes long even before the Incas, who were just one among many groups who already spoke forms of Quechua across much of Peru. Quechua arrived at Cuzco and was influenced by languages like Aymara. This fact explains that the Cuzco variety was not the more widespread. In similar way, a diverse group of dialects appeared while the Inca Empire ruled and imposed Quechua.
After the Spanish conquest in the 16th century, Quechua continued to see considerable usage, as the “general language” and main means of communication between the Spaniards and the indigenous population, including for the Roman Catholic Church as a language of evangelisation. The range of Quechua thus continued to expand in some areas. However, the administrative and religious use of Quechua was terminated when it was banned from public use in Peru in the late 18th century in response to the Túpac Amaru II rebellion – even “loyal” pro-Catholic texts such as Garcilaso de la Vega’s Comentarios Reales were banned. Despite a brief revival immediately after independence, the prestige of Quechua decreased sharply and it gradually became restricted to rural areas.
The oldest written records of the language are those of Fray Domingo de Santo Tomás, who arrived in Peru in 1538 and learned the language from 1540, publishing his Grammatica o arte de la lengua general de los indios de los reynos del Perú in 1560.