The Leonardi were an old and prominent Novarese family whose members included important church and civic officials and knights palatine.

Her family maintained close ties with Sant'Orsola as benefactors, which some speculate may have contributed to Leonarda's influence within the convent.

Lazzaro Agostino Cotta called her "la Musa novarese" (the muse of Novara) when he published a sonnet by A. Saminiati Lucchese which praised her musical talent, comparing it to the military prowess of Emperor Leopold I.

[5][page needed] Her published compositions span a period of 60 years, beginning with the dialogues of 1640 and concluding with the Motetti a voce sola of 1700.

Leonarda is credited with producing nearly two hundred compositions during that period, though her only works appearing before 1670 were the dialogues printed by Gasparo Casati.

It has also been suggested that once in the convent, she studied with Gasparo Casati (1610–1641), a talented but little-known composer who was maestro di cappella at the Novara Cathedral from 1635 until his death.

The only direct evidence linking the two, however, is Casati's Terzo libro di sacri concenti, which contains two dramatic dialogues, the earliest known compositions of Leonarda.

[10] Leonarda's intricate use of harmonies is one example of her influence in the cultivation of polyphonic music at Sant'Orsola, as many other Italian nun composers were doing at their own convents during the same period.

In one of her dedications, Leonarda stated that she wrote music not to gain credit in the world, but so that all would know that she was devoted to the Virgin Mary.

[3] She also noted in the dedication to Opus 10 that she wrote music only during the time allotted for rest so as not to neglect her administrative duties within the convent.