“Proprio!” The old man extended fingers as lean as the hands fading from the
walls behind us. “You see the palace roof over there, just to the left of the Basilica? The one with the row of statues like birds taking flight? That’s the Duke’s town palace, built by Palladio.”[1]
Proprio is Italian. It is an adjective describing possession, literally meaning someone's 'own', and in this context, 'his'.
[1] Wharton 1901, p. 2