Liber ordinum is the ritual book used in the Old Spanish liturgy consisting of the various prayers and the sacramental rites performed by the priest or the bishop. It was edited in 1904 by Marius Férotin who based his edition on the four manuscripts - three codices from the monastery of Silos (Archivo del Monasterio, ms. 3 and 4), the first one from 1039 (cod. A in the edition of Férotin), the second from 1052 (cod. B), the third, Rituale antiquissimum, from the eleventh century; and the codex from Madrid, the so-called Manuale mozarabicum (cod. 56, formerly F.224, in the library of Real Academia de la Historia), also from the eleventh century. The copyists used different old books of the Old Spanish liturgy, and various texts included in these Libri ordinum might come from different periods. However, according to Férotin, who based his interpretation on internal evidence, most of it was composed in the sixth and seventh centuries. He dated only a few prayers (e.g. the exorcism of oil, no. 1) to the later period.