The 13th-century documents were the laws for towns, cities and the general population. By the second half of the 16th century, documents were written in Castilian, backed by the Trastámara dynasty and making the civil and ecclesiastical arms of the principality Castilian. Although the Asturian language disappeared from written texts during the "sieglos escuros" (dark centuries), it survived orally. The only written mention during this time is from a 1555 work by Hernán Núñez about proverbs and adages: " ... in a large copy of rare languages, as Portuguese, Galician, Asturian, Catalan, Valencian, French, Tuscan ... ".