Artworks in the interior include a painting by Bergognone, Christ under the Grill; the tomb of Giovanni Bossi, attributed to Bambaia; a Baroque fresco cycle of the Life of St. Nicholas of Tolentino by Ciro Ferrari; and the Biblioteca Umanistica ("Humanist Library", 15th century).

The latter has three naves divided by granite columns, with frescoes of the Magisteri Sacrae Pagines commissioned by the Augustinians when they acquired the building.

The oldest existed as early as the communal age and was dedicated to St. Maria di Gargnano.

The new church was completed in the same age as the election of Francesco Sforza as duke of Milan 1451, and received the current name (meaning "St. Mary Encrowned") on that occasion.

In 1460, the duke's wife, Bianca Maria Visconti, commissioned the construction of a new church next to the oldest one, identical and connected to it, in order to create a single, larger edifice.