Book of polyphony for Vespers, copied by Diego Dorta (or d'Orta) under Francisco Guerrero's guidance for the Seville chapter. 125 folios. Some sheets corrected/amended probably reflecting Tridentine reforms adopted by Seville in 1575.
The book contains a series of psalms and a complete cycle of hymns by Francisco Guerrero, with the exception of four verses attributed to Rodrigo de Ceballos and Juan Navarro (two each). Some of the hymns are reworkings of previous versions composed by Guerrero c. 1546, which were revised again for publication in Liber vesperarum (Rome, Domenico Basa, 1584)
Many folios have been lost or removed. Juan Ruiz Jiménez has identifed a number of fragments from missing folios previously in this book, used in the 1700s as binding reinforcements on other mss in the archive. These fragments are collated in the DIAMM Virtual Manuscript Archive.