This large-scale, splendidly illuminated choir book was designed to be seen from the lectern by a group of singers during the Divine Office, the eight prayer services celebrated daily by monks, nuns, and clerics of the Catholic Church. It is the first volume of an antiphonal that probably consisted of seven separately bound books. The manuscript's illumination primarily takes the form of historiated initials marking each of the major holidays of the church year. The illuminator of this manuscript, known as the Master of Gerona, worked in Italy in the late 1200s. Familiar with the most recent trends in Italian panel painting and Byzantine icon painting, he knew how to convey a sense of weight, volume, and depth. Drawing on these innovations, he embedded scenes of surprising naturalism within the initials.