The origins of Fondi go back to the mythical Hercules, but it is certain that, the pleasant geographical position, the temperate climate, the fertility of the soil and the hills surrounding Fondi from prehistoric time, were inhabited by the Ausoni.

Between the 9th and the 8th century the town experienced Hellenic and Etruscan influence. Between the 7th and the 6th century B.C. it was under Volsci rule.
Later, Rome, after having overcome the Etruscans, wiped out the Volsci and gave  the town  its own local government administration.

In 338 B.C. Rome granted Fondi citizenship and it became part of the Emilia Tribe.
Two emperors of Rome, Tiberio and Sergio Galba, were from Fondi and also Pope S. Sotero, twelfth successor to Saint Peter. From the 3rd to the 19th century Fondi was bishop’s see with a glorious series of prelates. The “diocese” was suppressed in 1818 and in the Cathedral of Saint Peter there is still the bishop’s throne, decorated in cosmatesque mosaic by roman marble workers.

In the early Middle Ages Fondi was subjected to the invasion of the Lombards and in 846 it was destroyed by the Saracens. After the defence agreement against the Saracen devastation, in the 9th century, Pope John VIII surrendered Fondi to the Duchy of Gaeta. From 1297 it was governed by the powerful Caetani family who possessed a vast quantity of the territory of Latium. From the Caetani it passed over to the Colonna family and to Giulia Gonzaga.

The Countess of Fondi, Giulia, of extraordinary beauty, raised the county to the most prestigious ranks of the Renaissance courts. During Giulia Gonzaga’s reign  Fondi was  visited by artists and learned figures of the period. The beautiful Countess Giulia, widow of Vespasiano Gonzaga, captured the attention of the pirate Khair-ed-Din, Redbeard, who in August 1534 sacked the city to kidnap her.  Lady Giulia saved herself by performing a daring escape and found refuge in Naples where she died in 1567.

The county inherited by Giulia’s nephew, Vespasiano Gonzaga, passed over, by succession, to the Carafa family of Naples and to the German, Count Mansfeld, whose daughter, Eleonora, in 1721, sold the territory of Fondi to the de’ Sangro family who owned the county until the feudal abolition  in 1806.

On 6 November 1860 Fondi was occupied by Piemontese troops and was joined to Unified Italy.
Between 1943 and 1944, during World War II, it received 44 bombings.
Numerous houses in the historical centre were destroyed and a great number of civilians died under the ruins. Consequently there was a fast reconstruction in the post-war period, the urban perimeter was extended and public works were carried out.

In the last thirty years the districts of S. Magno, Le Querce, Salto di Fondi, San Raffaele have seen considerable urban development and have become densely populated towns active in agriculture and small trade.