 Jesuit priest Antonio Ruiz de Montoya, who in 1639 published the first written grammar of Guarani in a book called "Tesoro de la lengua guaraní" (Treasure of the Guarani Language / The Guarani Language Thesaurus), described it as a language "so copious and elegant that it can compete with the most famous [of languages]".The name "Guarani" is generally used for the official language of Paraguay.However, this is part of a dialect chain, most of whose components are also often called Guarani.