Franco-Roman antiphonary with material for the whole liturgical year (ff. 6r-240v), including part of a tonary (ff. 235r-241v), and a fragment of Hispanic rite antiphonary (ff. 1r-v and 3v) with material that in other Hispanic rite manuscripts is assigned for quotidian Sundays (e.g. E-L Ms 8, f. 281v onwards); ff. 2r-v, 3r and 4r-5v also seem to be misplaced or flyleaves extracted from a book very similar to the Franco-Roman antiphonary (same handwriting, notation and ruling of the parchment. The sequences in f. 2r have been identified as belonging to the Hispanic rite (e.g. in Fernández de la Cuesta, 1985, p. XIX). These chants, however, lack cognates in any other Hispanic rite manuscript (Códice Álvaro is given by Fernández de la Cuesta, as an Hispanic rite manuscript with a cognate, but this manuscript does not contain any other Hispanic rite material, so its sequence might be a Roman accretion). Before the current binding of GB-Lbl Add MS 30850, its fragment of Hispanic rite antiphonary in all likelihood served as the flyleaves of the Franco-Roman antiphonary, perhaps at its end. Maybe ff. 1r-v and 3r-v belonged to the same sheet 1r (hair) - 1v (skin) - 3v (skin) - 3r (hair); the last of these folios belongs to the Franco-Roman antiphonary, very likely recycling a blank page of the flyleaves. Drawings added to these folios also link them (and perhaps 5v too).
Notation: previous authors regard the notation of the main, Franco-Roman rite, part of this manuscript as 'Visigothic', i.e. as that used in most Hispanic rite manuscripts (see, e.g., Fernández de la Cuesta, 1985, p. X). This notation, however, is different in several respects from the Hispanic rite notation and it has recently been recognised as a distinct 'Silense' notation. As for the fragment of Hispanic rite manuscript, it has no trace of having born any kind of Hispanic rite notation, and later hands added Aquitanian notation to some of their words (ff. 1r-v). The resulting melodies, however, are not alike those in any cognate of Hispanic rite chants transmitted in this fragment - the Aquitanian neumes were very likely added informally as seems to be the case of the drawings on these folios. On f. 3v a few chants also have Aquitanian neumes in some of their syllables as well as Silense neumes, just as those in the main, Franco-Roman, part of this manuscript.
Date: because its main section contains Franco-roman liturgy and Hispanic-rite-like notation, previous scholars have proposed a copy-date very close to the official suppression of the Old Hispanic rite in the Iberian Península (i.e. ca. the Council of Burgos, 1080/1).
Provenance: the whole codex is ascribed to the abbey of Santo Domingo de Silos because it contains the earliest extant liturgy for this saint, and because it was preserved there from the middle ages (see Boylan, 1992, pp. 69, 71-2) until it was sold to UK owners in the nineteenth century.