Cartularies of Valpuesta

These cartularies contain an abundance of words of a developing Romance dialect and a copious list of place names in the Valley of Gaubea and the surrounding area.

The transcription took place during the formative period of the Kingdom of Castile, and it might reflect the early evolution of the Castilian dialect, although a written standard had yet to be established.

They are written in a very late form of Latin mixed with other elements of a Hispanic Romance dialect that corresponds in some traits with modern Spanish.

The preamble of the Statute of Autonomy of Castile and León mentions the cartularies, along with the Nodicia de Kesos, as documents that contain "the earliest traces of Spanish" (las huellas más primitivas del castellano).

However, there have been other documents with a claim to being the earliest in Spanish, notably, the Glosas Emilianenses (marginalia of circa 1000 CE from La Rioja).