Don Aurelio Bacciarini became a priest for the diocese of Lugano; he came to don Guanella from the parish ministry and spiritual director in the seminary. His training took place in the Milanese seminaries of Seveso-S. Pietro, Monza and Milan, corso di Porta Venezia, enjoying one of the scholarships instituted by St. Charles for clerics of the Swiss cantons. Simultaneously with the theology courses, he followed the lessons of the Pontifical Theological Faculty, so that he emerged as a doctor of theology. He had entered Seveso when he was fifteen. Prevented by the poverty of means from entering the seminary, having finished the schools of the town, he had added private study with a young parish priest, so he could be admitted immediately to the third gymnasium course.
In their native Valle Leventina, the large family - Aurelio was the seventh child - lived in decorous poverty, which became very harsh, bordering on poverty, when, at the age of 35, the father died of apoplexy: the eldest daughter had no that thirteen years old, Aurelio was three. One after the other, when they came of age, they all emigrated to America, except their sister Rosa. Aurelio, who was experiencing the drama of domestic difficulties, at the age of eight, begged his mother to let him go as a shepherd boy on the alp, to make the season from May to October: and she did it for six years. He was an exceptional boy: as he excelled in school, so he was in the church, assiduous altar boy, leader of the group: piety and goodness of mind went hand in hand. It was not difficult for the provost to discover the signs of his vocation. To his sister who jokingly asked him: "What will you be when you grow up?", He replied: "I want to become a priest". And immediately: «And I want to become a saint!».
Priest, his Bishop had sent him parish priest to Arzo, a small town in Mendrisiotto. He did not meet with good reception among the population, which was irritated by the transfer of his predecessor, against their will, but the esteem and affection that he earned with the open spirit of piety, with the zeal, with the total dedication , that soon the situation was reversed. He gave the parish a rhythm of spiritual activity, reorganizing existing associations, founding new ones, always gentle, but still strong in fighting evil and defending the rights of God and souls. He also gladly brought, and welcome, his word and his apostolic contribution to the nearby parishes. After six years, his bishop called him to the spiritual formation of young seminarians, spiritual director at the minor seminary of Pollegio. He stayed there for three years, carrying out his office with zeal and great amiability. However, for a long time he had cultivated the aspiration to a consecrated life and one of greater perfection. Meditating on which one to direct his choice, he stopped at Don Guanella and his Congregation, because it was recently founded and therefore richer in fervor, more humble and totally dedicated to the service of the poor. Entering the house, he was entrusted with the care of the aspirants and novices, then the spiritual formation of all the confreres. He was councilor and vicar general. He was fine with Don Guanella, fine with the poor, but he was tormented by the desire for a life of even greater austerity and contemplation. Considering it the will of God, not without having consulted, he secretly left Como and reached the Trappist abbey of Tre Fontane in Rome, where he took the name of Fra Martino. The common consternation was great, but above all that of Don Guanella, who, having succeeded in discovering his hiding place through his sister Rosa, went there immediately, after being at the feet of the Pope and being accompanied by his private secretary.
Don Guanella made a few but penetrating words ring in his ear: the Pope... souls... the will of God. In ten days of deep reflection, they penetrated his soul so much that, having left the trap, he presented to the community of S. Giuseppe al Trionfale. On his return, this was definitively confirmed by the words of the Pope who, in a private audience, said to him: "Your trap is there, in the Trionfale Quarter". He thought no more about it. The temple of St. Joseph had just been inaugurated, now it became a parish. Don Aurelio was the first parish priest. Triumphal, because the Via dei Trionfi, bathed a thousand times by the tears and blood of the vanquished chained for slavery, was then an area on the edge of the city, made up largely of slums, furnaces, reed beds and vegetable gardens. The fifteen thousand inhabitants were in material and moral abandonment. Don Aurelio's action, assisted by the brothers and sisters, was extraordinary. One day St. Pius X would say to Don Guanella: "I have a complaint to make to you: those priests of yours at St. Joseph's work too much". When on January 13, 1915, the earthquake devastated the Marsica and Don Guanella ran to bring the first urgent aid, Don Aurelio was at his side, to take charge of little orphans and the elderly to take to the houses of Providence. Then, when Don Guanella died on 24 October 1915, it fell to Don Aurelio, who was vicar, to console his grieving children and take over the leadership of the Work: by authority, the Holy See appointed him successor of the deceased Founder, a position he will also have to fulfill as Bishop until 1924, because, in January 1917, Don Aurelio was appointed bishop of Lugano. Benedict XV called him, who communicated the appointment to him; he did not listen to prayers and protests of unworthiness, he gave him the ring and the pectoral cross. "The will of the Pope, the will of God," commented Don Aurelio confidently. The consecration took place immediately, on the 21st of the same month, and the entry into Lugano on the 14th February. A quick visit to the main Guanellian houses preceded him, a greeting, an assurance that he would always be with them, brother and Servant of Charity.
It would take too long to follow him Bishop to Lugano, where he exercised an exceptional ministry. It will suffice to mention the pastoral visits to the most dissident and inaccessible places; to the oral word (up to seventeen sermons in one day!), and written in wonderful Pastoral Letters and spread with the foundation of a Catholic newspaper; at Eucharistic, Marian, and social Congresses; to the repeated, organized diocesan pilgrimages to the sanctuaries of Christianity; to the social works created for the disparate categories of needy, to the summer seminar for clerics. And then? Supreme gift, for the salvation of his people, he offered himself a victim. And God accepted it. They were fifteen years of physical suffering, of hospitalizations, of surgical interventions, which will make him say, jestingly: "I am the Bishop with only one ear, one eye, only one lung, only one hand, etc.". And, again, the dark night of the spirit, whose inner spasm, according to him, "exceeds all physical pain". Pius XI would define him: "The Job of the Episcopate", but he would refuse to accept his resignation from the diocese, as his predecessor Benedict XV had refused. The last act, of which he signed the parchment on his deathbed, was the consecration of his Ticino family to the Sacred Heart of Jesus, on the 50th anniversary of the creation of the diocese of Lugano. In the last week of his earthly life, he rediscovered the serenity and joy of going to meet his Lord. And the great meeting - it was certainly not by chance - took place on the eve of the feast of the Sacred Heart.
The faithful of his diocese keep his remains with veneration in the magnificent Sanctuary of the Sacred Heart in Lugano, built by him, and trustfully await, together with his confreres, to be able to invoke him as a saint on the altars.