Justinien Pense, an old friend of De Castro

Justinien Pense was a scion of the most important Lyonnais merchant families engaged in carpet manufacturing and trading with Antwerp. He occasionally travelled to Antwerp to learn the family business. De Castro met Justinien on one of these occasions in the beginning of the 1570s. Their collaboration in 1571 resulted in a luxurious manuscript (preserved in the Bibliothèque Nationale in Paris), for which Pense wrote the texts, while De Castro contributed the music.

In 1575 De Castro dedicated a new chanson book to Pense: the Livre de chansons nouvellement composé à troys parties, published by Le Roy and Ballard in Paris. This was De Castro's first 'international' publication.

On his arrival in Lyons around 1579 De Castro found the Pense family business in deep economical difficulties; the firm went bankrupts in 1580. Consequently De Castro's volume of 1580 is not dedicated to Justinien Pense, but to a relative of the Pense family, François De La Porte.