The manuscript sources of the Mozarabic or Old Hispanic liturgy have been thoroughly described and analyzed, with the exception of an early-eleventh-century book of saints' offices that has been considered missing since the late nineteenth century from the Cathedral Archive of Toledo. In October 2001, I identified this lost book as manuscript B2916 in the library of the Hispanic Society of America in New York, where it has been since its acquisition by the Society's founder, Archer Huntington. HSA MS B2916 is the only codex of the Old Hispanic liturgy preserved outside Europe. This manuscript is a curious book, comprising the offices for the feasts of Saint Martin (November 11), Saint Emilianus or Millán (November 12), and the Assumption of the Virgin (August 15). The matins lessons of the first two offices consist of the entirety of, respectively, theVitaeof Martin by Sulpicius Severus and of San Millán by Braulio of Saragossa. Because the manuscript was in a private collection and has remained uncatalogued, it has gone unnoticed for the last century, a period that saw the maturation of modern study of the Mozarabic rite. The contents of the book were not unknown during this time, however, because some specialists have consulted the copy (today in the Biblioteca Nacional in Madrid) made in 1752 by the polymath Jesuit Andrés Marcos Burriel. Indeed, it was Clyde Brockett's remarkably accurate handmade copy of the Burriel copy that made the identification of the manuscript possible, even at two removes. While the Burriel copy is useful, many important aspects of the original manuscript deserve notice.
