Isabella Leonarda, the name chosen by or perhaps for Isabella Calegari, when she became an Ursaline nun, is a remarkable figure in the history of Western music. It was not at all unheard of for women to compose music in times gone by, but in virtually all such instances, the music written is vocal: sacred motets -- such as we might expect nuns (for most woman composers in earlier times were nuns) to produce -- and/or secular madrigals. It is indeed unusual to find a seventeenth-century Italian woman like Leonarda putting together textless instrumental music in the new Italian Baroque fashion. Calegari, the daughter of a seventeenth century Italian aristocrat, was born in the city of Novara in 1620. As was still common in her day, most of the sons and daughters of the family were sent into church service, leaving only the eldest son to look after family matters. At age 16, then, Isabella entered the convent of Santa Orsala (Ursala), henceforth to be known as Leonarda. It is possible, though not proven, that Gasparo Casati, master of music at the Novara Cathedral, was her teacher in music. At any rate, in 1640, Casati organized the first publication of music written by her, in a volume otherwise devoted to his own music. She composed throughout her life and from the 1670s on, her music was regularly published, to a total of 20 volumes. She was, in addition, a very successful nun, eventually rising to the rank of Mother Superior for her convent and then becoming a Regional Counselor for the Ursalines. She died a few years into the new century, mostly likely in 1704. Sacred Latin motets form the backbone of Leonarda's life's work, but many of the other usual suspects -- psalms, masses, magnificats -- also appear in her catalog. Some of these works contain instrumental parts, supporting the vocal lines and at times shooting off on their own. And then there are the strictly instrumental works: 11 sonatas da chiesa for two violins (or other treble instruments) and continuo and one solo sonata for violin and continuo, published together in 1693 as Op. 16.