Carlo Zucchetti, was born in Vighignolo, a hamlet of Settimo Milanese (Ml), Italy, on November 29, 1914 at half past four in the morning, the second son of the four children of Giulio and Luigia Zucchetti. A simple family but with a clear Christian tradition; a few hours after his birth he was baptized in the parish church of Santa Maria Nascente.

Very early the child felt in his heart a vocation to the priesthood. On the advice of the parish priest he decided to enter the vocational college of the Discalced Carmelites in Monza; after completing his high school studies, in 1930, Charles asked to enter the Order of Carmel.

On July 11, 1930, at the Concesa Monastery of Milan, in the Shrine of the Divine Motherhood, Charles put on the habit of the Order of the Blessed Virgin Mary of Mount Carmel and was given the new name of Brother Marcellus of Mary Immaculate. His novitiate now began. On July 17, 1931, he made his first profession. After high school and philosophical studies in Milan, Brother Marcellus continued his theological studies in Piacenza. On 8 December 1935 he made his solemn profession. On 11^th of June 1938 he was ordained a priest.

After two short stays in Turin and Parma, he was transferred to Bologna where he remained for ten years. In 1948 he was sent to Ferrara to the St Jerome monastery: for thirty-six years the city experienced the incessant charitable service of Father Marcellus, especially as confessor and spiritual director. From 1951 to 1957 he held the position of Prior of the monastery. In 1960 he became Chaplain of the Paediatric Division of the St Anne General Hospital.

He died on July 13, 1984.

The Diocesan Inquiry into his «life, virtue and reputation for holiness» was opened in the Ferrara diocese on 8^th of December 2014 and closed on 25^th of September 2021.