Osanna Andreasi was born on January 17, 1449 at Mantua to the noble Mantuan Andreasi family — close to the ruling Gonzaga dynasty of the Marquisate of Mantua.
From early childhood Osanna displayed mystical-vocation signs. She received the Dominican Third Order (Tertiary) habit at the age of 14 (1463) — continuing to live at the family palace as a lay-Tertiary.
Osanna became the personal spiritual director of the Gonzaga ruling family — Isabella d'Este (Marchioness of Mantua from 1490, one of the principal Renaissance women intellectuals) and Francesco II Gonzaga received direct spiritual counsel from Osanna.
Osanna received the stigmata (invisible stigmata became visible at her death) and experienced the mystical-ecstatic phenomena documented in her Vita.
She died at Mantua on June 18, 1505 at the age of 56.

