The cryptoporticus was found at the beginning of the summer of 1954 during the works for the construction of the vicarage of the cathedral of Vicenza along the southern side of Piazza Duomo. To obtain the canonical cellars, the works included excavation up to a depth of 3.20 m. However, having arrived at a height of 3 meters, the workers came across a compact structure much harder than the earth and surrounding gravel, probably a fragment of the floor. In delimiting the structure it was noticed that below it appeared empty. With the help of a torch appeared what looked like a channel, not very deep and not very long. The cleaning and consolidation work immediately planned, revealed instead that it was a much more complex structure. The experts of the Archaeological Superintendency, immediately consulted, sensed that it could be a cryptoporticus from the Roman era. The cleaning, restoration, lighting and safety works that were carried out for three years were therefore prepared. In 1957, after laying the tile floor, the cryptoporticus was finally opened to the public.