The first documental proof of this is a deed of gift, dated April 15, 1396, whereby Gian Galeazzo gives to the monastery of the Certosa, landed property to the annual value of 2500 gold florins. On October 6 of the same year, he makes another endowment of property, yielding 5500 gold florins a year, besides an annual subsidy of 10,000 florins from his own private purse. The history of this beautiful building is much connected with that of Milan cathedral; the same architects--or rather brethren of the same Masonic Lodge--worked at both; and at one time Jacopo da Campione was _capo maestro_ of both works at once, spending a certain proportion of his time at both. Heinrich of Gmunden has had a good deal of credit for this building; so much so that a certain bust, said to be his likeness, was kept in the sacristy of the Certosa; and on the strength of that bust, the Germans erected a statue to him in Gmunden. But as he left Italy in July 1392, dismissed from Milan after a few months there, it is not probable that he could have designed the Certosa in 1396. Count Giulini was the first to draw attention to this error; and a learned archivist, Girolamo L. Calvi, had the good luck to discover in the archives of S. Fedele, the ancient register of the Administration of the building of the Certosa for the year 1396, which settles the matter completely. The master builder was Bernardo da Venezia, and Jacopo da Campione worked with him as designing architect and superintendent. On the official verification of this precious MS. on April 16, 1862, the bust of Heinrich da Gmunden disappeared from the sacristy of the Certosa. As a proof that the _Magistri_ mentioned were both employed, we will translate a few of the entries of the _Provveditore_ of the Certosa. "1396. _July 26._--In the presence of Pietro Barboti, official of the Administration, Berto Cordono, cordmaker, was paid for 138 lbs. of strong cord, for use in the designing and building of the church and cloister. The cord was consigned in June, at the order of Maestro Bernardo da Venezia, architect of the said _laborerium_" (Inzignerium dicti laborerii). "1396. _August 14._"--(This should, I think, be September 14). After registering several payments of wages to workmen who excavated the foundations, it is written--"Also the above-named Jacopo da Campione, for his superintendence of the works (tantum qui perseveravit superdictis laboreriis), together with the Duke's architects during fourteen days (_i.e._ the last days of August and the first two of the present September), at the rate of eight imperial soldi a day, as he had to find his own food."