Domingo de Santo Tomás, Grammatica o arte de la lengua general del Perú (1560)

The first grammar of Quechua, finished at Valladolid in January 1560 by a Dominican who had spent fifteen years in Peru. Its prologue to Philip II turns the grammar itself into evidence: a tongue this ordered cannot be called barbarous, therefore its speakers are not barbarians, therefore the men telling the king they may be treated worse than his other vassals are lying to him out of private interest.