On October 15 Guglielmo di Marco is paid 16 lire for his journey and eight days' employment in examining and judging the work of the church.
On October 18, 1387, we have payment to Maestro Simone da Arsenigo and ten companions (eleven in all), master builders. To Maestro Zeno da Campione and twenty-one companions (twenty-two including himself), master sculptors of "living stone" (pietra viva). The word which I translate companions is sotiis (Mag. Symoni de Ursanigo et sotiis, etc.), which would imply that they were all members (soci) of one society, and is thus valuable as a confirmation of the brotherhood in this guild.
In October 1387, Andrea da Modena, the Duke's architect, is again engaged, but only as adviser; for which he receives in dono fiorini venti; and Leonardo Zepo and Simone da Cavagnera are deputed to take note of his suggestions.
"1387. November 19.—For the payment of two large sheets of parchment consigned to Simone da Arsenigo." (These must have been to draw the plans.)
"1388. April 19.—Paid Maestro Marco da Frixone and soci for plaster to make models of the four piloni."
In another entry, noting the payment of 81 lire as salary, Marco da Frixone is named as Marco da Campione detto di Frisone.
Merzario is of opinion that such names as Marc the Frisian, who was one of the Campione school; Jacopo Tedesco, whom all old writers agree was Italian; Guglielmo d'Innspruck, also a Campionese, have been the cause of much misunderstanding, and have sent authors off on false scents. It was the custom, in the books of the Comacines, to name people from their provenienza, i.e. the last place they came from. Thus at Siena you will find Niccolò da Pisa, while at Pisa he is Niccolò di Apulia. Lorenzo Maitani was Lorenzo da Siena to the Orvieto people, and Lorenzo d'Orvieto to the Florentines. Marco il Frisone, born at Campione, is therefore a link between the German guilds and the Italian; he must have worked at Friesland, and probably brought back ideas of a more pointed Gothic from there.
These registers are ample proof that the builders just called in for the building of Milan cathedral were of the Lombard Guild, and chiefly of the Campione branch. It is not till 1389 that we find a single German name, and then a certain "Anichino (Annex) di Germania" is paid 16 soldi for having made a model of a tiburio (cupola) in lead, and Giacobino da Bruge, who falls ill while working at the church, has a slight subsidy given by the guild per amor di Dio. They are not mentioned again, and neither of them seem to be Masters.
That Simone da Arsenigo was chief architect at this time, not a doubt can exist. It is especially emphasized in a deed executed in December 1387. In it the Administration, "in consideration of their long and continued experience of the pure and admirable goodwill, and the opera multifaria which the worthy man, Magister Simone da Arsenigo, most worthy chief architect and master, has achieved in this church, by constant diligence, and wishing to remunerate him better (pro aliquali remuneratione bene meritorem), decide that whereas his salary hitherto has been ten imperial soldi a day, it shall now be raised to ten gold florins a month."
It is plain, however, that he worked in concert with the guild. Just as at Florence and Siena, great councils of the Masters, both architects and sculptors, were held to consider whether the foundations were strong before continuing the building, so in Milan a great meeting was called on Friday, March 20, 1388, in which all the Magistri were cited before their patrons, the Imperial Vicar-General, and the Council of XII. (In Florence the Arte della Lana took the post of President of the Works.) All the Magistri were charged to give their opinion on the building in its present state, and to suggest any improvements they could.