Authenticating many of Josquin des Prés's works, both sacred and secular, is a challenge for renaissance musicologists. In the first decades of the sixteenth century, when the Franco-Flemish composer's fame was at its height, the demand for his works far outstripped the supply; many counterfeits were created, with works by his pupils, as well as by other lesser composers, passed off as having come from the great man. There are even doubts about the authorship of the Credo Quarti Toni, included on the latest disc in the Tallis Scholars' series devoted to Josquin's masses, partly because it only exists in a single manuscript source. But the provenance of the two great works here, the Missa De Beata Virgine and Missa Ave Maris Stella, both canonically intricate and based on plainchant, is secure—the turbulent late De Beata Virgine survives in no fewer than 69 sources, while Ave Maris Stella was published in 1505. There are moments when the Tallis Scholars' beautifully shaped performances seem almost too seraphic, too smooth, but that's a minor quibble.