See too GREGOROVIUS, Geschichte der Stadi Rom, VIII (book XIV.  III, 2):  Die Luftschlosser furstlicher Grosse, wozu ihn der Papst hatte erheben wollen zerfielen.  Julian war der edelste aller damaligen Medici, ein Mensch von innerlicher Richtung, unbefriedigt durch das Leben, mitten im Sonnenglanz der Herrlichkeit Leo’s X. eine dunkle Gestalt die wie ein Schatten voruberzog. Giuliano lived in the Vatican, and it may be safely inferred from No. 1352 l. 2, and No. 1353 l. 4, that Leonardo did the same.

From the following unpublished notice in the Vatican archives, which M. Eug.  Muntz, librarian of the Ecole des Beaux arts, Paris, has done me the favour to communicate to me, we get a more accurate view of Leonardo’s relation to the often named GIORGIO TEDESCO: 

Nota delle provisione (sic) a da pagare per me in nome del nostro ill.  S. Bernardo Bini e chompa di Roma, e prima della illma sua chonsorte ogni mese d. 800.

A Ldo da Vinci per sua provisione d.  XXXIII, e piu d.  VII al detto per la provisione di Giorgio tedescho, che sono in tutto d. 40.

From this we learn, that seven ducats formed the German’s monthly wages, but according to No. 1353 l. 7 he pretended that eight ducats had been agreed upon.]

would acquire the Italian language.  He always promised, but would never do so.  And this I did also, because that Giovanni, the German who makes the mirrors, was there always in the workshop, and wanted to see and to know all that was being done there and made it known outside ... strongly criticising it; and because he dined with those of the Pope’s guard, and then they went out with guns killing birds among the ruins; and this went on from after dinner till the evening; and when I sent Lorenzo to urge him to work he said that he would not have so many masters over him, and that his work was for your Excellency’s Wardrobe; and thus two months passed and so it went on; and one day finding Gian Niccolo of the Wardrobe and asking whether the German had finished the work for your Magnificence, he told me this was not true, but only that he had given him two guns to clean.  Afterwards, when I had urged him farther, be left the workshop and began to work in his room, and lost much time in making another pair of pincers and files and other tools with screws; and there he worked at mills for twisting silk which he hid when any one of my people went in, and with a thousand oaths and mutterings, so that none of them would go there any more.

I was so greatly rejoiced, most Illustrious Lord, by the desired restoration of your health, that my own illness almost left me.  But I am greatly vexed at not having been able to completely satisfy your Excellency’s wishes by reason of the wickedness of that German deceiver, for whom I left nothing undone by which I could have hope to please him; and secondly I invited him to lodge and board with me, by which means I should constantly see the work he was doing