Liber misticus (type of book containing chants, readings and prayers for the cathedral ordo, i.e. vespers, matutinum and mass) with material for the offices for Saint Mary and for Christmastide. It also contains material that is normally part of a liber ordinum (type of book with the liturgy for the ministering of sacraments), namely the "Ordo ad commendandum corpora defunctorum". The liturgical material of this manuscript is preceded by two indexes, one written by Juan Bautista Pérez in the sixteenth century and another one commissioned by the Cardinal Francisco Antonio de Lorenzana y Butrón in the eighteenth century. Some folios are missing in the medieval codex, including the first and last ones. This is why it begins in the middle of the Ildephonse of Toledo's De Virginitate Sanctae Mariae, read at the office of Saint Mary (Annunciation, on 18 December), very likely at its matutinum service (due to the coincidence of the number of lections in this reading with respect to the number of matutinum missae in the Old Hispanic manuscripts preserving this matutinum without lacunae, namely, E-L Ms 8 and the Orational of Verona). So, its ff. 1r-44r have the office for Saint Mary (end of vigil and mass), and including its sermon - this is one of the few Old Hispanic misticus that includes a sermon in one of its offices. A later hand added a chant in Catalan point notation in f. 41v. The "Ordo ad commendandum corpora defunctorum" is in ff. 44r-45v; it is unusual to find this material in a misticus and its liturgical items are unique, including one of the few sequences copied in an Old Hispanic manuscripts (ff. 45r-v; see Brou, "Séquences", 1951). Following this, in ff. 46r-54v, comes the rest of the misticus, with the Assumption of Saint Mary office (without a sermon, as all offices in this manuscript except the Annunciation office). After this we find another section of this manuscript, also a misticus, which contains the Christmastide liturgy, starting with the Nativity office. This second section of the manuscript and the section that precedes it might not have been bound in this order originally, or perhaps they belonged to different codices; in fact, it is still possible to see that the booklet today starting with the Christmas office lost its first folio. It ends mutilated at the end of the Epiphany office's matutinum service.

Date: the palaeographically-based date proposed by Mundó (1965, p. 14) is ca. 1100 or later, though later in his table of sources (1965, p.21), he writes "XI-XII" (which is a century earlier than the date he proposes in p. 14) and this might be why most of the recent authors have this estimate. Other dates are: ninth to tenth century (Férotin, 1912; García Villada, 1923; Rojo and Prado, 1929; Pinell, 1965); tenth to eleventh century (Riaño, 1887); ninth to eleventh century (Clark, 1920); mid-tenth century (Brockett, 1968); tenth to twelfth century (Pinell, 1978); eleventh to twelfth century (Asensio, 2003; Janini and Gonzálvez, 1977; Hornby and Maloy, 2013); ninth to tenth century and also quoting Mundó's date (Randel, 1973; Gómez Muntané, 2001); tenth century but also quoting Mundó's date (Millares Carlo, 2009).

Origin: due to its similarties with other Toledan manuscripts associated with the Mozarabic Parish of Santa Eulalia in Toledo (namely, E-Tc 35.3, E-Tc 35.7 and/or E-Mn MSS/10001, some scholars (e.g. Mundó, 1965, and Brockett, 1968) have proposed that it was copied there. There is no evidence, however, to prove this possible origin (see Rojo Carrillo, 2018).

Scribe: "Sebastiano scriptor" in f. 54r, i.e. the first section of the manuscript. Due to the similarity between the script of all sections of this manuscript, both of them might have been copied by the same scribe.

Liturgical tradition: A.

Randel responsorial tone tradition: only two cases of Toledo A, two other cases slightly similar to Toledo B, and three cases with unknown tradition.