Antonio da Lonate set the central plan, for which a Bramantesque design, "Bramanti secutus exemplar" has been speculated; the latter would have executed the two portals to the west and south, and perhaps the elegant loggia in the tambour under the dome similar to the tiburium of the sanctuary of the Beata Vergine dei Miracoli at Saronno, which is attributed to Amadeo.

The church, in its typical forms of Romanesque architecture, was consecrated in 1346 by a bishop named Francesco, delegate of the archbishop Giovanni Visconti.

[1] All that remains today of this ancient building is the stone rondel placed at the top of the present presbytery and depicting in a relief the Madonna and Child.

[2] A number of people, mainly from the more educated part of the Bustoccan population, promoted this rebuilding: among them, the rectors of the basilica and founders of the capitular library of St. John the Baptist Francesco and Bernardino Crespi, the former of whom was also chaplain of St. Mary's; the Scuola dei Poveri; and the municipality.

I following subsequent studies and research carried out by Pio Bondioli, it can be said that Antonio da Lonate was responsible for the design of the basic wall structure, while the completion and embellishments were the work of Tommaso Rodari.

The compasses were replaced, and other interventions affected the windows, the balustrade, the floor, the wooden statues in the niches, and the organ, which was made later and then transferred to the church of Sant'Edoardo in Busto Arsizio, where it is still located today.

[6] Internally, the lower, square part, which is cut at the corners by diagonal arches forming niches and bonnets, refers back to Leonardo da Vinci's numerous studies of centrally planned churches, while the octagonal drum with a ring of niches (the crown of the 12 saints) and the eight nails of the covering vault echo the examples of the Church of Santa Maria di Canepanova in Pavia and of the Civic Temple of the Blessed Virgin Incoronata in Lodi and Santa Maria della Croce in Crema.

The rigorous cubic volume punctuated by pilasters is surmounted by a tiburium with gugliotti and lantern that interprets in lighter and more elegant forms the typology of the Lombard tradition.

Above the major arch a beam surmounts two triangular spaces ornamented with red stone roundels like those found in the doors of the Cathedral of Como.

[7] Of the shrine of Santa Maria there is an exact copy, but smaller, in Crespi d'Adda, a town listed as a World Heritage Site by UNESCO.

On the right wall, there is a triptych depicting the Madonna and Child with Saints previously attributed to Francesco Melzi, on deposit from the Pinacoteca di Brera

The symmetry and centrality of the figure of Mary (underscored by the twists of the cathedra) highlight the asymmetrical dynamism of the Child, who is placed sideways, as if sliding on the Mother's knee.