The Veneranda Fabbrica del Duomo di Milano is an ecclesiastical institution endowed with legal personality by ancient statutory determination with the purpose of worship and religion, which excludes all profit-making activities. Its earliest regulations were issued on 16 October 1387 at the behest of Gian Galeazzo Visconti who, with a deed issued on 24 October 1387, made the marble quarries of Candoglia available to the organisation.

The daily activity of the Veneranda Fabbrica is articulated into several operational sectors. Among these, in addition to welcoming million tourists who visit the Historical Complex yearly as well as the worshippers, there are also the construction and restoration sites (marble yard), the Duomo Museum, the Archives/Library and the Music Chapel.