The origins of the town are uncertain; various legends link them to mythological divinities and some studies think that the town was founded by the emperor Caracalla.
The most reliable hypothesis according to historical sources would date the origins of Bassiano to the X century with a first village composed of herdsmen and peasants, who found refuge here from the constant Barbarian raids.
In 1240 Pope Gregory IX gave Bassiano to Trasmondo Annibaldi as thanks for the help received during the struggle against the attempts at invasion made by Frederick II.
However, already in 1297 control of the city passed to the Caetans who remained lords of the area until the suppression of feuds, with the exception of a decade in which ownership was in the hands of the Borgias.
The Caetans started to leave signs of their control only from the XVI century with construction of the Baronial palace.
Commissioned by Bonifacio Caetani in 1554 the building was a valid refuge from the unhealthy climate and the perils of the marshes, until over the years it became a health resort.
The town was the birthplace of Aldo Manuzio (1449-1515), still considered to be one of the greatest printers of the Renaissance.