In the hierarchy of musical genres from the 15th and 16th centuries, the polyphonic mass, considered an act of homage to the Creator, held a predominate position. For the composition of the five parts of the Ordinary of the Mass — in which the basic liturgical texts are the same for each Mass (Kyrie, Gloria,Credo, Sanctus,Agnus Dei) — composers sought a form of coherence between these five very different texts (plea, praise, Act of Faith) by using a framework or theme throughout to create a solid musical unity. The most efficient way to achieve this was to base this on a musical model that was recognisable in each of the parts. This might be a Gregorian melody or indeed a polyphonic work that was either secular or sacred in inspiration. Of the five masses composed by Cipriano de Rore, three are based on works by Josquin des Prez, the prince of polyphonic music, admired and celebrated everywhere, and from an earlier generation.
De Rore was inspired by Josquin, notably by his Missa Vivat Felix Hercules, a mass written in honour of Josquin’s employer Ercole II d’Este de Ferrara. Josquin, who like de Rore had lived in Ferrara for a few years, had composed a mass in honour of Ercole I d’Este (Missa Hercules dux Ferrariae). Of the two masses that remain, one is based on one of his own songs or chansons, the other on that of a chanson composed by one of his contemporaries, the French composer Pierre Sandrin (Doulce mémoire), who was in the service of the King of France. Sandrin’s chanson Doulce mémoire was one of the most popular French chansons of the 16th century, as testified by the considerable number of instrumental arrangements and masses that are based on this song (besides those of de Rore, Thomas Crequillon and Orlandus di Lasso). His chanson is a sad, melancholic lovesong, which opens with a remarkable descending line sung by the soprano. This melodic theme follows throughout and gives vitality to the whole mass, in the manner of a leitmotif.
The second type of composition from the sacred repertoire at the time of de Rore was the motet, which, from Josquin des Prez onwards, aroused increasing interest. Those texts that were not to be used for the liturgy were taken from a wide range of sources: certain texts were taken from the Bible, with a particular preference for the Psalms or from the Book of Job (Parce mihi, Domine, a reading from the Funeral Rite), while others were taken from prayers and antiphons to the Virgin Mary (Agimus tibi gratias, a Prayer of Thanksgiving after Meals). As such, the secular motet gained in ignificant popularity, especially those in homage to a patron and often at his request. De Rore (as well as Willaert, his master) composed a motet in honour of Antoine Perrenot de Granvelle, Prime Minister to Charles Quint and Philippe II, who later became the Archbishop of Malines, written to a fragment of Virgil’s Aeneid, O socii, durate, with the words of encouragement from Aeneid towards his companions during a storm at sea.
One of the voices repeats the word Durate (‘Stand firm’) throughout the piece, like an ostinato, the phrase being the Granvelle family’s motto and which is found on a great number of coins minted in his honour, along with the picture of a ship in a storm. Religious motets were also associated with the personal preference of an employer or a patron, which is the case with the motet Infelix ego, and which is without doubt one of the most passionate of de Rore’s compositions. It makes clear reference to the Duke Ercole II d’Este de Ferrara, at whose court de Rore was maestro di capella from 1546 to 1559.