After Trent Borromeo reintroduced the practices of setting up columns with crosses on top at cross-roads, processions for the Sacred Nail and splendid translationes of important local saints. These initiatives are part of ferocious ideological battles on the validity of the cross as the supreme Catholic icon and on the relics of saints as intercessors. The massive protestant attack (Calvin,Chemnitz, the Centurians of Magdeburg) and the Catholic counterattack (Martiall, Harpsfeld, Cope, Baronio) are discussed. So too Borromeo’s reasserts the efficacy of relics and insists on the necessity of housing them properly; the elaborate ceremonies accompanying the translation of the relics of S. Sigismondo (1582) were part of the reinforcement of the doctrine on relics, as well as a proof of the antiquity of the Milanese church and its importance through S. Ambrose, and SS. Augustine and Simpliciano. For the ceremony of 1582 a colossal wooden arch was constructed in front of the Duomo (reconstructed by Giulia Sebregondi) and its iconography included scenes from the lives of Simpliciano and especially Ambrose, which were also illustrated in the choir stalls of the Duomo.