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[…]

Raphael also addressed the issue of architectural drawings in his famous Letter to Leo X (ca. 1519), which exists in several versions that differ in important ways. [n. 11] In all versions, Raphael laments the destruction of the ancient buildings of Rome and proposes an ambitious project to preserve them graphically, by means of measured architectural drawings. 

[11] Teodoro, Francesco P. di: Raffaello, Baldassar Castiglione e la Lettera a Leone X: "… con aituto tuo mi sforcerò vendicare dalla morte quel poco che resta…" (Bologna: Minerva Edizioni, 1994; revised and expanded 2003); John Sherman: Raphael in Early Modern Sources, 1483–1602 (New Haven: Yale University Press, 2003), I: 500–545.