The Massimo family is sometimes referred to as one of the oldest noble families in Europe. According to the Augustine historian Onofrio Panvinio (1529-1568) in his work "De gente Maxima" of 1556, the family descends in the male line from the ancient Gens Fabia or "Maximi" of republican Rome and from Quintus Fabius Maximus Verrucosus (c. 275 BC – 203 BC), called Cunctator ("the Delayer"). When asked by Napoleon (with whom he was negotiating the Treaty of Tolentino) whether the family descended from Fabius Maximus, the then Prince Massimo famously replied: «Je ne saurais en effet le prouver, c’est un bruit qui ne court que depuis douze cents ans dans notre famille» ("I can not actually prove it, it's a rumour that only runs for twelve hundred years in our family").
The Massimo family is also said to have provided two popes to the Catholic Church, both saints - Pope Anastasius I (died 401), who denounced the Origenist heresy, and Pope Paschal I (died 824), who resisted the Frankish Kings and was involved in one of the earliest attempts to Christianise Scandinavia.
The current family's better documented history traces back to a Massimo who flourished c. 950, and is identified in the person of Leo de Maximis by 1012. Thereafter the family grew in influence among the Roman barons, and played a considerable part in the history of the city in the Middle Ages, producing numerous cardinals, ambassadors, and civil and military leaders.
Massimo Massimo (died 1465) served as Rome's chief conservator, a post held by several subsequent members of the family. Luca Massimo (died 1550) was granted the title "Baron di Pisterzo" in 1544 and Fabrizio Camillio Massimo of the Arsoli branch of the family became "Marquis di Roccasecca" in 1686, both titles heritable by primogeniture.
Two branches descended from sons of Angelo Massimo (1491–1550), who became first lord (signore) of Intrafiumara in 1520; that of Tiberio, whose descendants became Dukes di Rignano and Calcata, and died out in 1907, and that of Fabrizio Massimo (1536–1633), who obtained the lordship of Arsoli in 1574. Massimiliano Camillo Massimo (1770–1840) of the latter line was granted the title Prince di Arsoli, heritable by primogeniture, by Pope Leo XII in 1826. His grandson, Carlo (1836–1921), 3rd Prince di Arsoli was made a Roman prince in 1854, which title also descends by primogeniture. His son Don Francesco, Prince Massimo (1865–1943) became postmaster of the Poste Vaticane, and his grandson Don Leone, Prince Massimo (1896–1979) became Duke di Anticoli-Corrado in 1904 by avuncular cession (the title having been created by Italian royal decree for his uncle Don Fabrizio Massimo in 1895).
Another grandson of the 1st Prince di Arsoli, Don Filippo Massimo (1843–1915), inherited the fortune and adopted the marital surname of the Prince's eldest daughter Donna Giusippina Massimo (1799–1862), who was the widow and heiress of Ottavio Lancellotti, Prince di Lauro (1789–1852). Although the senior line of Don Filippo's descendants retains the Lancellotti surname and title, his younger son Don Luigi (1881–1968), resumed the paternal name in the combination of "Massimo Lancellotti", and his descendants flourish, having been granted the Italian title "Prince di Prossedi" in 1932.
Although ancient and powerful, the post-medieval Massimo were not a sovereign family, yet heads of the family and other members contracted a remarkable number of marriages with members and descendants of reigning dynasties into the late 20th century, consistently so after the marriage in 1765 of Papal postmaster Camillo Francesco Massimo (1730–1801), Marquis di Roccasecca, to Barbara Savelli-Palombara (1750–1826), heiress to a handsome fortune.
Their son the first Prince di Arsoli, Massimiliano Camillo Massimo (1770–1840), married Cristina di Sassonia (1775–1837) in 1796, daughter of Xavier of Saxony, Prince of Poland and Lithuania, a younger son of King Augustus III of Poland.
Massimiliano's son, the 2nd Prince Camillo Vittorio Massimo (1803–1873), married Princess Maria of Savoy-Carignano (1811–1837] in 1827, the head of whose family became Charles Albert, King of Sardinia four years later and his son, King Victor Emmanuel II (1820–1878), became the first King of a united Italy in 1861.
The third Prince di Arsoli, Don Camillio Carlo Massimo (1836–1873) wed Donna Francesca Lucchesi Palli (1836–1923), a half-sister of the French Legitimist pretender Henri, Count of Chambord through her mother Princess Maria Carolina of Bourbon-Sicily (1798-1870) daughter of the Neapolitan King Francis I of the Two Sicilies and widow of Charles X of France's assassinated heir, Charles Ferdinand, Duke of Berry.
They had two sons, Francesco Massimo, 4th Prince di Arsoli (1865–1943), who married Donna Eleonora Brancaccio (1875–1943) in 1895 (daughter of Salvatore Brancaccio, Prince di Triggiano), and Don Fabrizio Massimo (1868–1944) who, in 1895 had been made Prince di Roviano and Duke di Anticoli-Corrado by Italian royal decree, and in 1897 married Princess Beatrice of Bourbon (1874–1961), daughter of the Carlist pretender to the French and Spanish thrones, Carlos, Duke of Madrid. Don Fabrizio and the Infanta had no sons, and in 1904 he ceded the dukedom of Anticoli-Corrado to his nephew Don Leone Massimo, son of his elder brother the 4th Prince di Arsoli.
Don Leone (1896–1979) also became 5th Prince di Arsoli in 1943, having in 1935 wed Princess Maria Adelaide of Savoy-Genoa (1904–1979), daughter of Prince Thomas, Duke of Genoa (1854–1931) and first cousin of then-reigning Victor Emmanuel III of Savoy, King of Italy.
The Massimo tradition of royal intermarriage continued when, in 1989, Carlo Massimo, 6th Prince di Arsoli (born 1942) married Doña Elisa Osorio de Moscoso y Estagna (born 1946), daughter of Pedro, Duke de Montemar (1904–1986), whose paternal great-grandmother was HRH the Infanta Luisa Teresa de Borbón-Cadiz, daughter of HRH the Infante Francisco de Paula of Spain (1824–1900) by her marriage to José Osorio de Moscoso, Duke de Sessa.
The princely family is represented by Fabrizio Massimo-Brancaccio, Prince di Arsoli and Prince di Triggiano (born 1963), and Stefano Massimo, Prince di Roccasecca dei Volsci (born 1955), whose heir is Don Valerio Massimo (born 1973). On the 21 May 2009 Prince Valerio reached the summit of Mount Everest.
The family were major patrons of the arts, with the brothers Pietro and Francesco Massimo acquiring fame by protecting and encouraging the German printers Sweynheim and Pannartz, who came to Rome in 1467, where the first printed books in Italy were produced in the Massimo Palace. In the 17th century Cardinal Camillo II Massimo was famous as the patron of both Velasquez and Poussin.
In the 16th century the Massimo were the richest of the Roman nobles. The Palazzo Massimo alle Colonne in Rome was built by the celebrated Sienese architect Baldassare Peruzzi by order of Pietro Massimo, on the ruins of an earlier palace destroyed in the sack of Rome in 1527. The curved façade is built on and dictated by the foundations of the stands for the stadium odeon of the emperor Domitian. The interior ceilings and vestibules are elaborately ornamented with rosettes and coffered roofs. The entrance ceiling is decorated with a fresco by Daniele da Volterra, who represented "Life of Fabius Maximus". The chapel on the 2nd floor was a room where the 14-year-old Paolo Massimo, son of Prince Fabrizio Massimo, was recalled briefly to life by Saint Philip Neri on March 16, 1583. The interior of the palace is open to public only on that day each year when the family receive the cardinals and other high officials to honor the event. Other notable events in the palace of the 16th century include various intra-familial murders. The palace is considered one of the most important early Renaissance mannerist masterpieces and remains the principal residence of the family, along with the Massimo castle in Arsoli.