The Cathedral Museum was opened in 1953 by the art critic Ugo Nebbia, but the idea took shape in the last quarter of the nineteenth century, when it became necessary to find a way of keeping together and preserving the huge amount of material connected with the history and construction of the Cathedral.
In 1948 the Fabbrica del Duomo obtained the concession from the State Property Department for nine rooms located on the ground floor of the oldest wing of Palazzo Reale, formerly the residence of the Visconti and Sforza families, renovated by the architect Piermarini in the second half of the eighteenth century.
At last suitable premises were available to house and exhibit the works to be preserved, which had significantly increased in number after the damage caused by the bombing in the Second World War.
The deterioration of many works of art, caused by atmospheric pollution, and the influx of further material from the Fabbrica storerooms and the Cathedral vestries soon made a larger exhibition area necessary.
In the Sixties the Museum was enlarged and re-opened with the addition of a further ten rooms - some of which were of great architectural prestige - by concession of Milan City Council, completely re-fitted and re-organised by the architect Ernesto Brivio on the basis of a historical-chronological project.
In 2013 the Museum re-opened after a long period of renovation and re-fitting under a project by the architect Guido Canali.