It was originally called Basilica di San Nabore after the saint whose remains it houses, but from the 13th century onwards, as the adjoining Franciscan monastery took possession of the monument, it took its new name from Francis of Assisi, founder of the order.

Later, the church continued to grow with the creation of numerous chapels by wealthy donors, who in exchange obtained the right to be buried in sepulchres created by renowned artists.

After a first destruction at the end of the 17th century and a reconstruction some ten years later, in 1697, the architectural style of the church became baroque, but its plan remained very close to that of the original building, although it lost ground area.

The most famous work is Leonardo da Vinci's Virgin of the Rocks, which forms the central panel of an altarpiece in a chapel dedicated to the Immaculate Conception.

[2][3]The history of the church of San Francesco Grande can be described in three main phases between its creation in the first centuries of the Christian era and its destruction in 1806.

[4] This history benefits from the archaeological research carried out during several excavation campaigns: a first one in 1939-1940 under the management of Aristide Calderini,[5] then a second one in two phases conducted in 2006-2008 and a third one in 2011–2012 on the occasion of the creation of a car park on the Place Saint Ambrose.

[6] In ancient times, the site to be occupied by the church of San Francesco Grande was located outside the city walls, a short distance from a gateway to the circus area and the imperial palace.

[12] Amongst these houses, there is in particular that of Filippo de 'Oldani, a Roman consul of the time of Nero who secretly converted to Christianity and buried the remains of St. Gervais and St. Protais here.

[13] Then, in the following century, the remains of St. Nabor and St. Felix, who died during the reign of the co-emperor Maximian Hercules, were transferred there from Lodi by Bishop Materne of Milan (episcopate after 314 and before 342).

[11] In 1256, by papal bull of Alexander IV, they received permission to build a church dedicated to the founder of the order, Saint Francis of Assisi.

[20] In 1475, Father Master Stefano da Oleggio proposed the creation of a chapel[1] dedicated to the Virgin Mary and in particular to the Immaculate Conception.

On this occasion, several prescriptions were issued by those in charge of the church, including one of an absolute nature, which forbids the creation of any opening to the outside of the building.

[1] Painters were commissioned to decorate the structure: the brothers Evangelis and Giovanni Ambrogio de Predis and Leonardo da Vinci.

[1][27] On the occasion of the creation of this altarpiece, the confraternity showed, despite its relative wealth, a great deal of penny-pinching, as evidenced by the dilatory measures and vague and unfulfilled promises for the remuneration of the participating artists.

[33] In the end, the church's footprint was reduced, but this did not prevent it[17] from remaining the second largest religious building in Milan after the city's Duomo.

[38] Finally, a barracks was built on its site: its plans were created by Lieutenant-Colonel Girolamo Rossi and its foundations partially used those of the pre-existing church.

[3] The external appearance of the building before its destruction-reconstruction in 1688 is described by a testimony in a letter dated 1686: "The old red brick facade, five windows, towers, crosses, with three doors, the middle round, and many elements with sepulcri et statuae".

[48] In addition, the monument loses more than a quarter of its length out of the 114 metres it had previously measured,[34] as the entire part corresponding to the former Basilica of San Nabore is not rebuilt on its first five pillars and becomes the church's new atrium (i.e. its entrance courtyard surrounded by porticoes).

[49] The interior is described by a testimony from 1696 which mentions a "vast, large, beautiful and dazzling choir, decorated with stucco and very clear thanks to the width of the windows".

Indeed, as the historian Patrick Boucheron, a specialist in the Middle Ages and the Renaissance, notes, "the proliferation of gentilice chapels in Milan can be seen as the architectural translation of a political requirement for the 'social visibility' of the patronage of the oligarchy in the service of the prince".

Beatrice d'Este, in particular, took charge of its decoration in 1333, before the condottier Francesco Bussone da Carmagnola - a commoner who joined the Visconti family by marriage - was buried here in 1432.

The structure was originally located between the pillars in front of the chapel of St John the Evangelist, and was later transferred to the Borromeo Palace on the Isola Bella, where it remains today.

[59] Between 1495 and 1500, Vincenzo Foppa painted the panels of an altarpiece that seems to have been intended to decorate the chapel of St. John the Evangelist belonging to the Borromeo family.

It seems that two other panels belonging to the upper register can be identified with the paintings representing an Angel Gabriel and an Annunciation to the preserved Virgin in the Borromeo Palace in Isola Bella.

[60] Later, after 1503, the altarpiece of the Immaculate Conception was installed, consisting in particular of Leonardo da Vinci's Virgin of the Rocks (completed only in 1508) and framed by the Angel musicians by Giovanni Ambrogio de Predis and Francesco Napoletano.

Around 1510, the Franciscan friars commissioned Ambrogio Borgognone to paint a picture entitled St. Francis Receives the Stigmata, depicting the holy founder of their order.

The destruction of the church in 1807 was carried out with no regard for the works on display: explosives were even used, without any real precautions, to the extent that the neighbouring buildings were damaged.

[63] The ecclesiastical authorities were moved by this and obtained permission from the minister in charge to recover the remaining works, which the latter accepted on condition that "this would not cost the administration anything".