He constructed a chapel for his patron, in the church of S. Giacomo Maggiore, and painted for it a St. John preaching in the Wilderness, and the Division of the Elect from the Damned.The Cardinal Poggi next employed him in the erection of a chapel in the Basilica della Santa Casa, Loreto, where he painted the Nativity, the Presentation in the Temple, the Transfiguration and Decollation of St. John.In Milan he worked also as a civil architect, projecting the Spinola, Erba Odescalchi and Prospero Visconti palaces.In Pavia, again for Cardinal Charles Borromeo, Tibaldi designed the monumental building of the Almo Collegio Borromeo: a university boarding school set on an airy courtyard with a perfect quadrature, characterized by the elegant Serlian architectural design of the two orders of loggias.Following the severe and ascetic character of the Counter-Reformation Pope, who had wanted a functional but not sumptuous construction for his college, Tibaldi interpreted this approach of the client by creating a three-storey building, with a square plan, imposing but not empty scenographic, with internal spaces functional to the community life that takes place there.