And indeed the amount of music he has found there seems almost incredible: 5,500 pages in the old Jesuit mission of Chiquitos; and a further 4,000 pages in the Moxos mission, all of them written in the 16th, 17th and 18th centuries and amounting to over 80 polyphonic masses, operas, sonatas and other instrumental music, with some of the pieces incorporating texts in Indian languages.