In the 12th century, they are recorded as minor feudatories in the areas of Tuscania and Orvieto, several members holding political positions in the latter commune.

Six years later Niccolò Farnese saved Pope Urban V from the attack of Giovanni di Vico, first in the castle of Viterbo and then in that of Montefiascone.

The loyalty to the Papal cause meant that the Farnese were granted confirmation of their possessions in the northern Lazio and given a series of privileges which raised them to the same level as more ancient and powerful Roman barons of the time, such as the Savelli, Orsini, Monaldeschi and Sforza of Santa Fiora.

The family substantially increased its power in the course of the 15th century, as their territories reached the southern shore of the Lake Bolsena and Montalto, largely due to Ranuccio the Elder.

Ranuccio's son, Pier Luigi, married a member of the ancient baronial family of the Caetani (that of Pope Boniface VIII), thus giving the Farnese further importance in Rome.

Paul III died in 1549 and his political role in the Curia passed to his grandson Alessandro, who remained an influential cardinal and patron of the arts until his death in 1589.

In 1545, Paul handed over, from land once belonging to the Papal States, further territories in northern Italy to his son, who took the additional title of Duke of Parma.

Paul thus established his family as an Italian ducal dynasty, a project at which the Borgia Pope Alexander VI had failed.

Despite intrigues by Charles V, the Pope reacted promptly and soon established Ottavio, Pier Luigi's son, on the ducal throne.

Ottavio was given the additional title of Duke of Piacenza and initially established his court there, where work was begun on a huge Farnese palace on the banks of the River Po.

II, tierced in fess: Gules, papal tiara or, surmounted by two keys argent and or in saltire and interlaced at their intersection with a cord azure (for Papal State), overall, argent, five escutcheons in cross azure, each charged with five plates in saltire, a bordure gules charged with seven three-towered castles or (for Portugal).