It was written between 1286 and 1290 by an anonymous monk of Santo Tirso Monastery for Count Martim Gil de Riba de Vizela.
Originally divided into five parts, only the first and part of the second survive in a 17th-century copy, now in Lisbon, Biblioteca Nacional da Ajuda [pt], 47-Xlll-10, at folios 30–41.
The geographical scope of the text is mainly the Entre Douro e Minho in the old north of the country.
The purpose is to defend the nobility against the centralizing tendencies of King Denis, especially apparent in the surveys and inquiries of 1284.
The Livro Velho traces the nobility as far back as the Kingdom of Asturias.