Jon, I tried to open my Italian<-->software last night, but I couldn't, so I couldn't check for "tresor." This question, though, brings to mind "fenestra" (which I learned in Firenze [and a current Italian dictionary] as the word for "window" and "fenesta" (which is the form used in the Neapolitan "O Sole Mio."

Though I could not find my sheet music for Dormi, Dormi, O Bel Bambin' before I left town today, I think I copied the lyrics accurately from my sheet music into my computer files, from which I posted the lyrics above.

Genie