Liber Ordinum (type of manuscript which contains chants, prayers, hymns and preces for the ministering of sacraments and blessings). Hispanic liturgical tradition: A. Responsorial tone group: La Rioja (Randel 1969). The manuscript is divided into two parts: Ritual (ff. 0-54r) and Mass (ff. 54v-155v), and it was probably dated in the same period of Silos’ Liber Ordinum (Rojo y Prado, 1929). The notation is Hispanic vertical, but it has some pages with Aquitanian palimpsests, specifically on f. 24r, 26r, 28v, 29r, 30v, 31v, 32r, 32v, 33r, 33v, 34r and 35r. This pages show an amount of 18 pieces in Aquitanian that are almost the only ones that are preserved in double notation and there are almost the only ones that can be transcribed indeed: thirteen antiphons, three responsories and two preces of the "De uno deffuncto" Votive Office (Gómez Muntané 2001, Rojo Carrillo 2011). Its repertory is very related to E-Si Ms-4.

The most probably cradle of this manuscript is mentioned on f. 1r: "...qui locum istum Sancti Emiliani confesoris consecrasti". This "Sancti Emiliani" could be the San Millán de la Cogolla monastery (Ruiz García, 1997, Díaz y Díaz, 1991).

White parchment with modern binding. Visigothic script, of liturgical type. It is well preserved despite the lack of pages at the beginning and at the end sections. The copy was performed by a single scribe, as observed in the colophon "Dominicus Scribtor" on f. 123r. Its illumination shows epigraphical rubrics, rich miniatures and a wide range of capital letters: anthropomorphic, zoomorphic, laceries and lackluster color letters.