The Most Holy Trinity Church was demolished around 1968 to be rebuilt at another site on architect Fritz Metzger’s project, from 1964 to 1967.
Founded by the reformist priest Liprando around 1070 in a property called pons Guinizeli, at the end of St. Rocco’s fountain running along the current Via Niccolini, it also included a rectory.
Being in the middle of the battle against the Milanese Church, Pope Urban II agrees to take the church out of the Ambrosian leadership and puts it under the protection of the Holy See, with a certificate dated 1099.
After the death of Liprando, which occurred in 1113, the land and the buildings are assigned as farming land to the Order of Saint Benedict from St. Simpliciano church.
When on July 7, 1251 Pope Innocent IV is in Milan, upset by the role of public collectors played by the Humiliates Order, he prevents them from carrying out the activity and assign them the church of the Most Holy Trinity as well as the lands.
In 1291 the church was assigned to priest Bonvesin de la Riva, belonging to the third order of the Humiliates. Chronicles report that Bonvesin picked up the Pope’s call to ring the bells to solicit the residents to prayer three times a day: in the morning for the Ave Maria, at noon for the Angelus and at the sunset for the Vespers. The practice could have been inaugurated right in the church of the Most Holy Trinity.
In 1571 the order was dissolved tragically and the church was incorporated into the parish of St. Protaso.
It is only in 1608 that the Most Holy Trinity becomes an autonomous parish, thanks to the intervention of Cardinal Borromeo.
In 1616 the church was completely destroyed by a fire; The only surviving part is the bell tower.
The reconstruction was realized applying coherent architecture with the spirit of time.
In 1768, the parish documents report that a consortium of women was resident in the buildings of the church.
Between 1900 and 1902 the church acquired a new facade, designed by architect Giuseppe Boni: in neo-Baroque style, it hosts a sculptural group, located on the main door and modeled by the sculptor Orazio Grassoni. A new bell tower is built between 1909 and 1911 on the project of the engineer Giovanni Ambrogio Locatelli, keeping the old bell tower.
The church is used for parish services until the end of the 1960s.