The ancient Ecclesia Sancti Petri ad Ulmum, which has survived in its Romanesque form, arose 12km west of Milan along the Roman road to Novaria. It is first mentioned in a document of circa 1100 and was subsequently altered during the course of the following centuries.
The first investigation, which it is hoped will lead to more extensive interventions, involved a geophysical survey and several trial trenches and identified structures of importance for the architectural definition of the monument. It also brought to light a stretch of an unknown pre-Romanesque building which may help to shed light on the earliest phases of the church of S. Pietro all’Olmo. A legend tells that during Diocletian’s persecutions the tortured but intact body of San Vittore was found, guarded by ferocious lions, in a wooded area called ad ulmos, situated along the road from Milan to Vercellas, as is in effect S. Pietro. It is evocative to imagine that a small Lombard church was later built on the site of the miraculous find. (Roberto Mella Pariani, Laura Simone Zopfi)