The importance of Velletri, in the history of the area, setting it apart from all other towns of the Castelli enough to get her to consider a special case. The ancient Volscian city of Velester (or Velcester) gave very hard time to the Romans, who with difficulty managed to subdue under King Anco Marzio, twice broke free from this yoke, and only in 338 BC was finally transformed into municipium with the name of Velitrae. But even before Rome were the Etruscans spread their culture to this area in their attempt to reach the Pontine plain and the south of Latium, of this attempt have been many inscriptions and pottery. In imperial times the patrician villas were numerous in this area and that of the gens Octavia grew the future Augustus. In 410 A.D. the invasion of the Goths reached the town and Alaric sacked hard Velletri.

In medieval times Velletri was still a thriving city and staying faithful to the Pope managed to maintain their independence without being subjected to various lords and families in other villages of the Castelli Romani dominated every area with several upsets over the years. The city was one of the first independent municipalities of Latium, ruled by a power which had the motto "Est mihi et libertas papalis imperialis" his program. In 1299, the authority elected as Pope Boniface VIII, later clashed with Rome and was finally covered by the dispute between the Lambs and Wolves, that is, the Guelphs and Ghibellines: This internal struggle between supporters of the Pope's power and supporters of the imperial power was shared in many Italian cities (Just think of the Florence of Dante).

Its strategic location (The Appian Way passes through Velletri before entering the Pontine plain and head towards Naples) has made the place too great a node in the event of conflict, in 1744 became embroiled in a battle between Austrian and Neapolitan troops, including the 1798 and 1799 was at the center of clashes between French troops and bands sanfediste.

In 1849, for the defense of the Roman republic, Garibaldi earned an important victory against the Bourbons. During the Second World War the city suffered a major bombing in 1944 shortly before the liberation of Rome by German troops and was reduced to a pile of rubble, ready to rebuild the city back to the importance it had before the war and was the basis for development that puts today Velletri the most important cities of Latium. From the point of view, the city offers scenic views of the surrounding area with ease, you can admire the mountains of Ciociaria and Lepine, to the sea Terracina and the Pontine plain. Inside the modern Velletri you can grasp the remains of the past and present examples of urban planning, not always a human scale, the remains of Roman Velitrae are often hidden by the buildings and streets. The complex of the Cathedral of St. Clement, dating from 327 AD, hides the remains of a Roman temple dedicated to Mars, the Church of the Stigmata of St. Francis actually stands on the site of a temple Volsci; most of the discoveries are now far from Velletri, however, until 1800 the important Museo Borgia, now depleted despite the preservation of unique pieces, was known throughout the world and even Goethe he was amazed despite its distance from Rome.

The church of St. Mary of the Trivium, with clearly visible next to the Tower, is one of the most emblematic buildings of the city, built in 1353, as remembered by a plaque, withstood wars and bombings. Worthy of note are the Town Hall restored after the last war, cites a statement introducing the monumental door Napoletana from the south to the city, recently restored and home of the sommeliers of the Castelli Romani.

A curiosity: in 1780 Pope Pius VI had to restore the Appian Way, abandoned since the late Middle Ages to the raids of pirates and replaced with more upstream pathways that crossed the other countries of the Castles, the track was expected to focus directly on Terracina from Genzano, cut off from the way the most important city in Velletri. The citizens of Velletri as did the initial design was modified by restoring the bend of the Appian Way to the city and in turn the population TU shoulder the burden of financing the reconstruction of the road.