Guillaume Costeley

Guillaume Costeley [pronounced Cotelay](1530, possibly 1531 – 28 January 1606) was a French composer of the Renaissance. He was the court organist to Charles IX of France and famous for his numerous chansons, which were representative of the late development of the form; his work in this regard was part of the early development of the style known as musique mesurée. He was also one of very few 16th century French composers of music for keyboard. In addition, he was a founding member of the Académie de Poésie et de Musique along with poet Jean-Antoine de Baïf, and he was one of the earliest composers to experiment with microtonal composition.

Costeley was born in Fontanges-en-Auvergne, coincidentally the same town as contemporary composer Antoine de Bertrand. Nothing is known of him prior to his arrival in Paris in or before 1554, at which time he met, and became acquainted with the music of, such diverse figures as Jean Maillard, Jacques Arcadelt, and Sandrin. It was through Sandrin, who had recently worked in Italy, that Costeley probably became interested in the latest trends in Italian scholarship, particularly the theories of Nicola Vicentino, some of which involved composition using microtones. Costeley's only microtonal composition, Seigneur Dieu ta pitié, was apparently written at exactly the time that Sandrin was in Paris.

During the late 1550s Costeley rose in prominence in Parisian musical life, being published by Le Roy and Ballard in 1559. Since Le Roy was closely connected to the royal court through the family of Catherine de Clermont, who was to become the Countess of Retz, it is probable that his influence was significant in Costeley's rise. By 1560 Costeley had been appointed to the royal court, as organist, music teacher to the ten-year-old monarch, and composer of chansons for the royal chamber.

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