Cristoforo of the Institute of the Daughters of Mary Help of Christians, born at Mornese Monferrato, in the hamlet of Mazzarello, on 9 May 1837, died at Nizza Monferrato on 14 May 1881.
She belonged to the Pious Union of the Daughters of Mary Immaculate, founded by the parish priest, and had begun to gather the girls of the village in a rented house to teach them catechism and needlework. When the parish priest spoke to St John Bosco about this group, he saw in it the fulfillment of a dream and a desire to have a feminine branch alongside the Salesians, which had already been founded. He therefore entrusted Maria Domenica Mazzarello with the task of putting the idea into practice, after a period of formation, and leaving its direction to her.
After a period of probation, she and her ten companions received the religious habit on 5 August 1872 and were given the rules specially written by the Saint. With the opening of new houses, Maria Domenica was elected Superior General and gave vigorous impetus to the spread of the Institute. At her death, she left more than 30 houses in Italy, France and Latin America with 250 religious.
She was beatified on 20 November 1938 and canonized on 24 June 1951. Feast day: 14 May.