Italian composer, born in Savigliano in Piedmont. His father, Guglielmo Fergusio, came from Scotland (his name must have originally been Fergusson) to Savigliano, a small and peaceful town that was ceded to the Savoy region of France from 1349 onward, at the time of the peace of Cateau-Cambresis (1559). he worked as a "rector in the humanities schools of the Commune" from 1576 to 1600. Giovan Battista was born in 1582 and started studying music, as an early anonymous biographer says, "very young," soon revealing a very promising talent, such that "on account of his age and the way in which music was played at that time, he was universally appreciated." In about 1601 he moved to Parma, both to study law at the University which had just been refounded by Ranuccio I Farnese, and to continue studying music with Claudio Merulo, the organist of the Santa Maria della Steccata church. In the two years he lived as a musician in Parma, Giovan Battista gained "much esteem" and not only in the eyes of his teacher, athough he did not make a definitive commitment o the music profession.
By 1603 he was back in Savigliano, where he began working successfully as a lawyer. He did not, however, stop cultivating music, "playing the organ and, above all, finding new, unusual and gracious tunes to dance to". In the dance music genre, Fergusio proved exceptionally inventive and creative, such that "our Duke (Charles-Emmanuel the 1st) and his children, the Serenissime princes, took great pleasure in hearing his dance works, especially on the viols, which were incomparably wonderful and above all the Courantes, of which more beautiful ones were never heard, and which were played in all parts of the world, especially in France and Spain." Unfortunately, to this day none of these dances has been found. Like the Musiche e balli a quattro voci con il basso continuo (Venice 1621), composed by Sigismondo D'India for the Duke of Savoie's Turin Court, the Piedmontese musician's dances could be significant evidence on the other side of the Alps of the French style in the dance repertory.
In February 1608, Fergusio performed in the tragi-comedy La Margherita, produced in Savigliano as part of the festivities for the marriages of the two daughters of Charles-Emmanuel the 1st, Margherita to Francesco Gonzaga and Isabella to Alfonso d'Este. For the same occasion, Monteverdi composed L'Arianna and Il Ballo delle Ingrate.
In 1612, the Venetian editor Giacomo Vincenti accepted for publication the only work by Fergusio that is known to survive, the Motetti e Dialogi per concertar a una fino à novi voci, con il suo Basso continuo per l'Organo. Apparently he thirty-year-old Fergusio intended this publication to be the prelude to a promising artistic and editorial career. Instead, his musical career was cut short. Painful arthritis "spreading to the joints in his hands" rendered him "unable to play the organ" and "took away his will to compose and to listen to music."
From 1613 onwards, traces of the presence of Fergusio are progressively fewer. He continued his job as a lawyer, as a mayor and a member of the Town Council, and as a member of the Congregation of the Assumption. A premature heart attack carried him off at the beginning of 1628.