COmprises two original MSS (ff.0-99r; ff.99v-125r) now bound together. Folios 0-99 in choirbook format; folios 106-124 written as six consecutive parts.

Copied at the Escorial (Charles Manns), possibly by Fray Pedro de Estremera. Brought to the collegiate church of S. Pedro in Lerma by Gabriel Díaz before 1616 when it was inventoried there (CerVSP, pp. 201-3); listed in subsequent inventories up to & including 1747. Once owned by Federico Olmeda de San José (1865-1909) of Burgos, a Spanish organist, historian, and bibliophile; acquired by The Hispanic Society ca. 1911 at Hiersemann Antiquariat sale of items from Olmeda's library.

original covers: black, leather covered boards

staff height 23mm

original ink foliation, 1-101 (f.12-13 numbered 22-23; unnumbered folio after f.61)

almost all folios from 1-55 have double line border in red ink, and initials in red ink. initials on 0v-1r are watercoloured.

original index on f.125r lists first 3 pieces in the order they appear

Paper: 2 distinctive types - up to f.55 (light) and f.56 onwards (heavier)