MASSIMO, or MASSIMI  , a Roman princely family of great antiquity, said to be descended from the ancient Maximi of republican Rome . The name is first mentioned in 1012 in the person of Leo de Maximis, and the family played a considerable part in the history of the city in the middle ages . The brothers Pietro and Francesco Massimi acquired fame by protecting and encouraging the German printer Ulrich Hahn, who came to Rome in 1467 . In the 16th century the Massimi were the richest of the Roman nobles . A marquisate was conferred on them in 1544, and the lordship of Arsoli in 1574 . To-day there are two branches of the Massimi, viz. the Principi Massimo, descended from Camillo 'Massimiliano (1770-1840), and the dukes of Rignano, descended from Francesco Massimo (1773-1844) . One of the sons of the present Prince Camillo Carlo Alberto, Don Fabrizio, married Princess Beatrice, daughter of Don Carlos of Bourbon (duke of Madrid), the pretender to the Spanish throne . The Palazzo Massimo in Rome was built by Baldassare Peruzzi by order of Pietro Massimo, on the ruins of an earlier palace destroyed in the sack of Rome in 1527 . See F . Gregorovius, Geschichte der Stadt Rom (Stuttgart, 1880) ; A. von Reumont, Geschichte der Stadt Rom (Berlin, 1868) ; Almanach de Gotha; J . H . Douglas, The Principal Noble Families of Rome (Rome, 1905) .