AMONG THE VARIOUS FIELDS of musical research still open to investigation, perhaps none is more widely open than that of Spanish and Portuguese music of the I7th and z8th centuries. I am thinking primarily of the keyboard music written on the Iberian peninsula during that time, although the statement also applies to the vocal and possibly other instrumental fields. Until about 30 years ago only one Spanish keyboard composer was generally known, Antonio de Cabez6n (ca. I500-66), whose works were published by Pedrell as early as 1895 in the Hispaniae schola musica sacra volumes. Not until 1927 was another important step taken, when Angles began the publication of the Opera omnia of Cabanilles, who died in 17 I2, almost I50 years after Cabez6n. Only recently has this large gap been filled to some extent by Kastner's new edition of Correa de Arauxo's Libro de tientos (1626) and of Manoel Coelho's Flores de misica (1620). There still remain two large gaps, one between Cabez6n and Correa-Coelho, the other between Correa-Coelho and Cabanilles. There exists extensive source material for both periods which, however, has only recently become available for study. We are concerned here with the first of the two periods.2 Who were the immediate successors of the great Cabez6n? We know only one of them, his son Hernando, who in 1578 edited his father's works under the title Obras de mzisica, including among them a few compositions of his own. Most of these are not original works but arrangements of vocal pieces. They are, however, of considerable interest because they are among the earliest of their kind to reveal a more subtle and individual approach to the business of intabulation than was customary during the I6th century. Probably a younger contemporary of Hernando (who died in 1602) was Bernardo Clavijo del Castillo, born perhaps about 55o0. He was chapel master and, from 1588 on, organist of the vice-royal court at Naples. In 1593 he became professor of music at the University of Salamanca and in I603 he was appointed court organist of King Philip III. He died in Ma-