Sabine Hyland in the context of "Classical Quechua"

Classical Quechua or lengua general del inga is either of two historical forms of Quechua, the exact relationship and degree of closeness between which is controversial, and which have sometimes been identified with each other. These are:

1. the variety of Quechua that was used as a lingua franca and administrative language in the Inca Empire (1438–1533) (henceforward Inca Lingua Franca or even Imperial Quechua). Since the Incas did not have writing (though some Quipus might have been narrative, following a logosyllabic pattern, according to some experts like Gary Urton and Sabine Hyland), the evidence about the characteristics of this variety is scant and they have been a subject of significant disagreements.
2. the variety of Quechua that was used in writing for religious and administrative purposes in the Andean territories of the Spanish Empire, mostly in the late 16th century and the first half of the 17th century and has sometimes been referred to, both historically and in academia, as lengua general 'common language' (henceforward Standard Colonial Quechua). It is Standard Colonial Quechua in this second sense that is abundantly attested in writing, notably in the famous Huarochirí Manuscript, and that this article primarily describes.

There are also some less common and typical uses of the term "classical" in reference to other Quechua varieties, whose relationship to the abovementioned ones is also controversial, namely: