When she was nine years old, Eleonora returned to Florence, and was placed by her mother as a convent-school girl in the monastery of the Clarisse of San Jacopo in Via Ghibellina and, once eighteen, taken away by her own mother to be married without notice to Orazio Landi, a Florentine patrician. Since the marriage the spouses lived separate, for reasons that seem to be related to the state of health of the husband.
From the first boarding schools for girls to the congregation of the "Ancille of the Holy Virgin"
While her husband, struggling with financial difficulties lived retired in his villa in Mugello, Eleonora moved to her brother's house where she welcomed, starting from 1626, the first orphan girls in order to take care of their education. For about twenty years she devoted herself to the spiritual education of women, overcoming slander, suspicions and ecclesiastical inspections, and searching continuously for housing best suited to the norms of life established by her for this all-female community, to develop her own constitution which, approved on 25 October 1645 by the then Archbishop Niccolini, sanctioned the official birth of the first of the two lay congregations founded by Montalvo: the "Ancille of the Holy Virgin Mary Mother of God".
The congregation of the "Ancille of the Holy Trinity" at Villa La Quiete
Having purchased the Villa della Quiete from the Medicis, she took possession of it on 11 June 1650 together with the "Ancille of the Holy Trinity", the second congregation she founded. In 1657 the Villa housed thirty-three "Ancille". The girls would enter the convent between the ages of five and seven, and at fifteen they could then decide whether to marry, become a nun or stay in the Congregation to devote themselves to prayer and the education of other young girls.