This website provides basic information about musicians and non-musicians related to music books in the database; it is not intended to present a full biography of musicians, but to establish useful connections with their sources, institutions, locations, works, documents, and bibliography. Under "Locations" of a composer's entry we list all the locations in which he lived and those in which his music is currently found; under "Institutions", we list only the institutions where he worked or to which he applied for a position through the so-called "oposiciones". Whenever possible, we'll try to indicate the approximate periods of service in each institution. The distinction between "Locations" and "Institutions" provides a useful overview about the dissemination of a composer's works; for instance, Sebastián Aguilera de Heredia (1561-1627) worked only in two cathedrals in Huesca and Zaragoza, but his music is found in at least twenty-two locations in Spain and the New World.