Pinerolo (pēnārôˈlō) [key], Fr. Pignerol, city (1991 pop. 35,331), Piedmont, NW Italy, at the foot of the Alps. It is an agricultural and industrial center. Manufactures include paper, textiles, machinery, chemicals, and processed food. First mentioned in the 10th cent., Pinerolo was a strongly fortified citadel that passed to the house of Savoy in the 13th cent. It was often in French hands from 1536 to 1814, and the fortress was made a French state prison. Nicolas Fouquet, an official of Louis XIV, died in the citadel after 19 years of imprisonment (1680), and the Man with the Iron Mask was held there for some years after his seizure in 1679. The city has an 11th-century cathedral (frequently restored).