Diana was born around 1201 at Bologna to the noble Andalò family — her father a consul of Bologna, the Andalò family among the principal Bolognese aristocratic-consular families of the period.
Around 1219, at the age of 18, Diana first met St. Dominic de Guzmán at Bologna — Dominic then in the course of the founding-mission of the Order of Preachers at Bologna. Captivated by Dominic's personal magnetism and the new-Order's apostolic vision, Diana sought Dominican-affiliated religious life.
In 1222, after Dominic's death (August 6, 1221) and the election of Bl. Jordan of Saxony as second Master of the Order, Diana was received as a Dominican-affiliated woman-religious by Bl. Jordan.
In 1223, Diana founded (with support from Bl. Jordan) the Dominican Monastery of Sant'Agnese at Bologna — one of the earliest Dominican women's-monastic foundations (preceded only by the Dominic-founded Roman convent of San Sisto of 1221). The Sant'Agnese Monastery became one of the principal early Dominican women's-monastic communities.
Diana's personal correspondence with Bl. Jordan of Saxony — fifty surviving Latin letters composed 1222–1236 — is one of the principal medieval Catholic spiritual-friendship correspondences. The letters illustrate the specifically Catholic 13th-century spiritual-friendship between the Master-General of the Dominican Order and the foundress of the first Dominican women's-monastic community, in the parallel of the contemporary Franciscan Francis-and-Clare spiritual friendship.
Diana was joined at Sant'Agnese by Bl. Cecilia Cesarini (former abbess of the Roman San Sisto) and Bl. Amata — the three Bolognese Dominican women's-monastic saints of the early Order.
She died at Sant'Agnese on June 10, 1236.

