Housed inside the monumental Palazzo del Senato, the State Archives of Milano, under the supervision of the Ministry of Cultural Heritage, conserves a huge store of documents on its over 40 km of shelf space – testimony to the history of the duchy and city of Milano, from the Longobard era to the present. Originally the site of the Collegio Elvetico, founded in 1579 by archbishop of Milano Carlo Borromeo for the training of secular Swiss clergy. Some of Milano’s most famous architects of the 17th and 18th centuries worked on the Palazzo, including F. Mangone, F. M. Richini, G. Quadrio, G. B. Quadrio, and L. Pollack. By the late 1700s the Palazzo served a variety different functions and underwent modifications by architects G. Piermarini and M. Segrè.