The long letter is a detailed account of the preparations and travels related to the visit of Count Annibale Altemps to Borromeo, Imperial Count since 1560 and husband of Hortense Borromeo. The cardinal details his travels in the following weeks in order to meet Count Altemps, without upsetting his own plans. Cardinal Borromeo, Archbishop of Milan, dedicated the last years of his office to the evangelization of the Swiss valleys, attempting anti-Protestant expansion towards the Cantons, from the Grisons to the neighbouring valleys. He created a branch of the Milanese seminary in Arona, the Helvetic College (1579), in Milan for the Swiss and the Grisons), the college for the Grisons in Ascona (1584), etc. In this letter, using Arona as his base, he organizes trips to Varalle, Canobio, Luino, Valtravaglia, Chiavenna, Valtellina, etc. The letter was written on October 19, 1584: just two weeks later, on November 3, he passed away upon returning from a pastoral visit to Lake Maggiore.