This illuminated manuscript of the Siete partidas (Seven-part code), on parchment in Gothic script, dates from the 13th–15th centuries. The codex is important for several reasons. It was written in one scriptorium (except for Partida I, which was added in the 15th century) and it includes the complete Partidas with their ornamentation, and bibliographic clues that shed light on their origins. This body of law, commissioned and begun by Alfonso X and supplemented by later reforms, constitutes the most widely known legal system that governed Spain from the Middle Ages to the modern era and influenced the law of some of its former colonies. Its implementation took place from the reign of Alfonso XI and the Cortes of Alcalá de Henares of 1348, in which the Partidas are mentioned as a body of law. The manuscript is divided in seven parts, one for each Partida. Included are a general index (not well done for Partida II) and a table of contents at the beginning of each Partida with the titles of its laws; those for Partidas V and VII are missing. Partida I deals with canon law; II with peerage law, including the rights of kings and grandees; III with procedural law and the administration of justice; IV with civil law, especially marriage law and human relations; V with commercial law; VI with succession and estate law; and VII with criminal law. In its entirety, the body of law regulates all social relations. The manuscript is illuminated with ornamented corners and miniatures at the beginning of each Partida, illustrating the topic treated. For example, at the beginning of Partida I, the pope introduces the king to the Savior (folio 106 r.); in III, the king, on his throne, administers justice (folio 191 r.); in IV, there is a scene of the baptism of Jesus Christ (folio 294 r.); in IV, the king, as the supreme representative of justice, signs a contract with several people (folio 331 r.); in VI, a dying man dictates his testament (folio 379 r.); and in VII there is a representation of a tournament (folio 415 r.). Some capital letters are decorated in burnished gold and various colors, with blue and red being predominant, and some of them have elegant flourishes. Red is used in the titles and captions. The manuscript originally belonged to Alvaro de Zúñiga, first duke of Arévalo, chief justice of the kingdom, who was married to Leonor Pimentel. This provenance is reflected in the coats of arms that adorn the front page and in its binding. The manuscript later was part of the library of the Catholic kings, as can be seen by its rich velvet case. The binding is in Moorish-gothic style, in embossed leather on wood. Inside the covers is the Zúñiga–Pimentel coat of arms. This richly decorated cover was later protected by the royal house with a blue velvet case, adorned in Morisco enamel set in silver. The floral and heraldic motifs predominate in the four clasps and in the two royal initials “Y” (Isabel) and “F” (Ferdinand) and in the two bundles of arrows.