*Article* **Things Always Come in Three: Non-Invasive Investigations of Alexander and Roxane's Wedding Room in Villa Farnesina**

**Manuela Vagnini 1,\*, Chiara Anselmi 2,\* , Michela Azzarelli <sup>1</sup> and Antonio Sgamellotti 3,4**


**Abstract:** Non-invasive optical spectroscopical analyses were conducted on the three main walls of Alexander and Roxane's Wedding Room in Villa Farnesina, Rome. The north and the east walls were frescoed by Sodoma in 1519. The decoration of the third wall was subsequent and neither the author nor the period is known. The north and east walls underwent various restorations, some even very invasive. For these reasons, the supposed remaining original parts of the two walls by Sodoma were studied and compared with the third one, aiming to obtain more information about its author and epoch. The results show the use of the same pigments for the three walls. In particular, the same yellow pigments including lead antimonate, the use of enamel blue with Bi impurities whose use is time-limited, and the use of a certain kind of purple hematite. The commonality in the pictorial technique also emerged, especially in the yellow parts, painted in the same way on each wall. This information, and documentary sources, reinforce the hypothesis that the third wall was decorated shortly after the death of Agostino Chigi by someone who was well-acquainted with the materials and techniques used by Sodoma for the other two walls.

**Keywords:** non-invasive investigations; portable/reflectance spectroscopy; portable Raman spectroscopy; lead antimonate; enamel blue; caput mortuum
