The architectural buildings was built by Galeazzo Maria Sforza in fulfillment of a vow made in 1466 . In fact, the death of his father Francesco Sforza, he was at the service of the King of France and, while attempting to return to Milan to be proclaimed Duke, miraculously he survived an ambush. It was completed in 1472, while the church is consecrated with the title of " St. Mary Annunciation " in 1477. The church and convent were entrusted to the Order of Observant Franciscans , which derived from the preaching of St. Bernard who was able to gain to his cause Filippo Maria Visconti and to convert a large number of Milanese nobles.
In 1810 the convent was suppressed, and is adapted to house the headquarters of Abbiategrasso male Hospital of the Incurables, with substantial changes to the original structure. On the right side of the church, is the arched entrance to the first courtyard overlooked by an impressive body on two levels belonging to the primitive core of the building, then used as a dwelling, a building built at the beginning of the last century to accommodate the laundry and the dormitory as well as the most recent section, dating back to the fifties of the last century.
Through two passages with vaulted ceilings, there is the access to the second courtyard , wider and more regular that the former, on which it faces a double gallery surrounding the courtyard on three sides , and who cared , in the section adjacent to the church , the cemetery of the Friars . There is also the body of the building that housed the sacristy , the refectory , the kitchen and the dormitory . The premises of the refectory were fractionated over time and used in part as a dwelling and partly as laboratory; now you can admire frescoes , such as the "Resurrection " and 'the "Last Supper" dating back to the one at the end of the 400 and the other about two centuries later , and that has already been completed the restoration. To the north of the building lies the church for a long time occupied by shops , houses and a warehouse of building materials . The bell tower has been abandoned for decades.
The church has a single nave, it had the facade painted with the representation of "Annunciation" and on the sides of the big arch there were two chapels and the south ones was decorated with paintings depicting " Galeazzo Maria Sforza and the Blessed Virgin " with the Saints Joseph and Catherine on the right and Francis and Bernardine on the left. Between the two chapels, the first chorus was accessible, and there the "Passion " was painted and then in the main chapel the " Mysteries of the Virgin" and other subjects were represented as well.