The All Souls' Day Mass, 2003, featured Jacob Clemens' " Missa defunctorum," a medieval requiem mass presented by Polyhymnia .

Jacob Clemens (called Clemens non Papa ) was one of the later representatives of the school of Flemish composers, who collectively so dominated European music in the Renaissance period. In the hierarchy of that school he was of the fourth generation - if Dufay be taken as the first, Ockeghem as the second, and Josquin as the third - with Lassus and de Monte yet to come as the fifth and last. Unlike many of his colleagues who were open to all the innovations of their time, Clemens remained a conservative figure, preferring to continue with the introverted, reflective style of composition which so well suited his predecessors, resisting the increasingly humanistic style of the Italians.

Although it was the fashion amongst Flemish musicians to study and work in Italy, there is no evidence that Clemens ever did. This disinterestedness for outside inspiration makes Clemens an unusually valuable contributor to the Netherlands school, preserving his old-fashioned view while compatriots like Willaert (in Venice), de Rore and de Wert (itinerant in northern Italy), and later Lassus (in Munich) were moving slowly out of the Renaissance altogether. It could be argued that this move was the death of the Netherlands school, since in the end the Italians were much better at Baroque thought and Monteverdi's revolution was an entirely Italian affair. All the pieces on this recording show essentially Flemish thought at its most typical.

Clemens' posthumous reputation has been coloured by some strange circumstances - his enigmatic nick-name, his lack of precise dates and therefore of anniversary years; and the fact that much of his finest work is to Dutch texts (the Souterliedekens ) - again not a detail which is true of his leading compatriots. The nick-name seems to have been nothing more than an affectionate joke. There is no obvious reason why it should have been necessary to distinguish him from Pope Clement VII (who anyway died in 1534), nor why he should have been confused with the poet Jacobus Papa in Ieper (Ypres), who happened to have the same first name as him. Clemens spent most of his life in the Dutch-speaking part of modern Belgium, especially in Bruges, Antwerp and Ypres; but he also regularly visited the southernmost parts of present-day Holland, appearing for instance in Leiden, Dordrecht and 's-Hertogenbosch. It was for the Marian Brotherhood in 's-Hertogenbosch in 1550 that he wrote Ego flos campi .