Gesualdo's strength was his ability to combine a variety of unconventional strategies into the service of a deeply felt and psychologically effective whole. Gesualdo's style, once regarded as unique, has helped to open up an entire field of study relating to the avant-garde of the late sixteenth century, sometimes referred to by scholars as the "Mannerist Revolution." This movement vanished once Baroque style came to the forefront of music in Italy.
Gesualdo was born the second son of the Second Prince of Venosa, probably in the town that bears his family's name. After receiving musical training from Stefano Felis and Giovanni de Macque, Gesualdo's earliest known work appears in 1585, when he was 19. That same year, his elder brother died at 20, making marriage an imperative for the younger Gesualdo. The bride was his first cousin, Maria d'Avalos, at age 25 already twice-widowed. They wed in Naples in 1586, and the following year an heir was born. Gesualdo discovered d'Avalos in an affair with the Duke of Andria. On October 17, 1590, Gesualdo, assisted by three servants, killed them both. The incident attracted public outrage, but there would be no trial, as authorities from both Church and State convened to dispose of the matter. Gesualdo's father died in 1591, and another marriage was arranged to Donna Leonora d'Este, taking place in Ferrara in February, 1594. In Ferrara, Gesualdo came into contact with court composer Luzzascho Luzzaschi and his "secret music," and became a close friend of the poet Torquato Tasso. Upon returning to his estate late in 1596, Gesualdo resolved to travel no more. In 1597, d'Este bore Gesualdo a second son who died in 1600, an event that plunged the Prince into a deep despair. The couple separated in 1608, and in 1610 d'Este began divorce proceedings against Gesualdo, but changed her mind and returned. In 1613, Gesualdo's elder son died, and Gesualdo himself followed on September 8 at age 47. He was known to be violently asthmatic his whole life. In later years, he would pursue masochistic practices which chronically served to weaken him physically, his spirit already broken by a decade of insanity.
Gesualdo's six books of Madrigals constitute the main body of his work. Books I and II (1594) are rooted in standard practice, but when compared to contemporary settings of the same poetry, they reveal a stubbornly individual mind at work. Book III (1595) shows a decreased reliance on pre-existing settings, and by Book IV (1596), all the texts used are original. Here, Gesualdo's mature style begins to emerge. Books V and VI did not appear until 1611, but in these editions, Gesualdo states the madrigals were written "15 years" prior to the date of publication, and were printed only to protect the works from plagiarists. While essentially diatonic in character, madrigals such as Beltà, poi che t'assenti and Moro lasso contain music which modulates so frequently it results in a disoriented sense of key. Dissonance is used liberally; passing tones cross relate, and there are passages of stepwise chromatic motion resulting in a suspended tonality. Gesualdo published three books of sacred music. The first two, entitled Sacre Cantiones, appeared in 1603, and in the second book Gesualdo expanded his usual five-part texture into six and seven parts, though two of the partbooks are lost. The third book, Responsoria (1611), represents Gesualdo's final musical statement. It is entirely in his late style, and the responses composed for the Good Friday service contains some of the most assured and eloquent music that Gesualdo composed.