Matteo Rocca and Ronan Dunphy peered into the gloom on the second floor of the 12th-century palazzo in Genoa, Italy.

This had once been the grandest part of the seven-story palace, with the highest ceiling, the tallest windows and the most elaborate painted decoration. It was here, on the “piano nobile,” or noble floor, that the aristocratic family who had once occupied the building would have entertained guests.