highly dangerous. All three works contain retrospective features harking back to the earlier Tudor tradition of Mass settings which had lapsed after 1558, along with others which reflect Continental influence and the liturgical practices of the foreign-trained incoming missionary priests. Mass for Four Voices, or the Four-Part Mass, which according to Joseph Kerman was probably the first to be composed, is partly modelled on John Taverner's Mean Mass, a highly regarded early Tudor setting which Byrd would probably have sung as a choirboy. Taverner's influence is particularly clear in the scale figures rising successively through a fifth, a sixth and a seventh in Byrd's setting of the Sanctus. All three Mass cycles employ other early Tudor features, notably the mosaic of semichoir sections alternating with full sections in the four-part and five-part Masses, the use of a semichoir section to open the Gloria, Credo, and Agnus Dei, and the head-motif which links the openings of all the movements of a cycle. However, all three cycles also include Kyries, a rare feature in Sarum Rite mass settings, which usually omitted it because of the use of tropes on festal occasions in the Sarum Rite. The Kyrie of the three-part Mass is set in a simple litany-like style, but the other Kyrie settings employ dense imitative polyphony. A special feature of the four-part and five-part Masses is Byrd's treatment of the Agnus Dei, which employ the technique which Byrd had previously applied to the petitionary clauses from the motets of the 1589 and 1591 Cantiones sacrae. The final words dona nobis pacem ("grant us peace"), which are set to chains of anguished suspensions in the Four-Part Mass and expressive block homophony in the five-part setting, almost certainly reflect the aspirations of the troubled Catholic community of the 1590s. Gradualia The second stage in Byrd's programme of liturgical polyphony is formed by the Gradualia, two cycles of motets containing 109 items and published in 1605 and 1607. They are dedicated to two members of the Catholic nobility, Henry Howard, 1st Earl of Northampton and Byrd's own patron Sir John Petre, who had been elevated to the peerage in 1603 under the title Lord Petre of Writtle. The appearance of these two monumental collections of Catholic polyphony reflects the hopes which the recusant community must have harboured for an easier life under the new king James I, whose mother, Mary Queen of Scots, had