Antonietta Zanelli was born in Castel Guelfo (Italy) on June 17, 1887. Born into a wealthy family, her father was the pharmacist of the village and her mother, Countess Maria Acquaderni, was the sister of Count Giovanni Acquaderni, founder of the «Society of Italian Catholic Youth», the current Catholic Action (therefore Antonietta was the niece of Giovanni Acquaderni).

After the age of 15 she began to discern her vocation. Directly in her innermost being: in the generous and simple prayer in which she asked Jesus directly what he wanted from her after the illness that had prostrated her to the point of fearing the end of her life. On that occasion Antonietta had promised: «Jesus, if you heal me I will become a nun to quench your thirst for souls» and she was healed. Then, at the invitation of the parish priest of Castel Guelfo, she committed herself at the age of 20 to liturgical singing, catechesis to children and works of charity in the emerging Pious Association of the Little Apostles of the Sacred Heart.

In 1919 she lost both her parents, 3 months apart, after Antoinetta had lovingly cared for them. Her family ties were over and she devoted herself entirely to her life of consecration in the community and service.

But there were still obstacles to the realization of her vocation, as Don Giuseppe Mazzanti would later confide: «It was the will of Providence that the roads that Signorina Antonietta Zanelli tried to travel were constantly hindered by people». These were problems of relationship in the community, with jealousy and misunderstandings, and the same happened in the management of the «Abandoned Childhood» Institute of Imola, so Antonietta was transferred with her Sisters to Santa Caterina, where Don Bughetti received them with great joy and the collaboration lasted many years..

Meanwhile, upon arriving in Imola in 1920, Antonietta had sought a confessor and had been recommended to Don Giuseppe Mazzanti, who from 1911 to 1928 was confessor in the Cathedral. Antonietta always carried within her the world and the anxiety of the apostolate and with time she also learned to know the path of the «little way» of Sister Therese of the Child Jesus, precisely through her spiritual director Don Peppino.

Mother Maria Zanelli died in Imola, Bologna, on December 15, 1957.

The Diocesan Inquiry into her «life, virtue and reputation for holiness» was opened on 3 June 2016 at the diocese of Imola.