San Bernardino alle Ossa is a church in Milan, northern Italy, best known for its ossuary, a small side chapel decorated with numerous human skulls and bones.

At that time, a cemetery and a small Christian church dedicated to Santo Stefano were established in this part of the city, which was situated just inside the Roman walls near Porta Romana.

The growing population of Milan and the continued importance of Santo Stefano meant that the cemetery attached to this hospital quickly filled with the remains of the dead, leading to the need for a more permanent solution to house the bones.

[1] In 1210, a small chamber was built specifically to house bones from the overcrowded cemetery, marking the beginnings of the ossuary for which the site would later become famous.

His design significantly expanded the original structure, making it more prominent and suited to the growing number of pilgrims and visitors who were drawn to the ossuary.

During this time, a hidden crypt was discovered beneath the church, containing additional bones and relics, which added new layers to the site's historical and spiritual significance.

After Oliva’s death, his work was continued by his successors, including Luigi Cortella and Giuseppe Arienti, who implemented further conservation initiatives.

Their focus was on preserving the unique bone artwork, enhancing the lighting to illuminate the space better, and repairing parts of the structure that had deteriorated over the centuries.

The ossuary's vault was frescoed in 1695 by Sebastiano Ricci with a Triumph of Souls and Flying Angels, while in the pendentives are portrayed the Holy Virgin, St. Ambrose, St. Sebastian and St. Bernardino of Siena.

Above the single altar, made of fine marble and featuring the symbols of the Passion of Christ, stands a statue of Our Lady of Sorrows.

She is depicted wearing a white robe, covered by a black cloak embroidered with gold, kneeling by the dead Christ with her hands clasped in prayer.