The church was constructed between 1598 and 1606 following the design of Ascanio Vitozzi, who was buried here after his death (1615). Originally born as an isolated building on the side of the road (the wide road of Dora Grossa) with an annex to house pilgrims, it is now attached on one side to a structure from the late 18th century and, on the other side, to Via XX Settembre. The facade was reconstructed by Angelo Marchini in 1830 on order of the Confraternita della Santissima Trinità, who had regained possession of the complex in 1818. Inside, the entire programme of decorating is attributed to Filipppo Juvarra on an ambitious order of the aforementioned Confraternita while the frescoes of the dome are by Francesco Gonin and Luigi Vacca. The side altars, designed by Carlo di Castellamonte and Michelangelo Garove, are also resplendent. The vestry is also extremely precious, typically Baroque, designed by Ignazio Agliaudo di Tavigliano.
