in the year 956 Aldobrandino De Nobili received by Ottone I of Saxony the investiture of the village of Labro and other 12 castles and settlements in the contrada of the Duchy of Spoleto and the suburbs of Rieti. The Emperor gave to the family coat of arms with the crowned eagle, symbol of the Holy Roman Empire and the fish, which was the domain of the family on the waters of the region.
Originally the fortification of Labro consisted of an imposing square tower above the village which was in turn surrounded by a road of arrocamento protected by defense walls comprising seven other towers. In 1498, the family was excommunicated by Pope Sixtus IV. The reason of the excommunication was the killing of a priest which took place at the hands of Giovanni de' Nobili. Consequence of the excommunication was the destruction of the great tower and part of the village. The withdrawal of the excommunication, preserved until today in the archives of the castle, foresaw that instead of the large square tower was built a church. The family remained the walls, where Giordano De' Nobili built the new residence for the family, still inhabited by his descendants. The origin of the surname Nobles derives from the title with which were designated the Lords of Labro.
In 1575 Gerolamo de Nobili marries with Virginia Vitelleschi and at the request of the family of Virginia, in particular of the Brother Muzio Vitelleschi, general VI of the Jesuits, the surname Vitelleschi was added to the noble and the two coats of arms were united in a single coat of arms. The act that officially sanctioning the union of surnames and coats of arms is preserved in the archives capitolini. A genuine copy is located in the Noble Archive Vitelleschi, in Labro.
A large coat of arms in wood in the shape of a heart in black and gold, made to celebrate the union between the two families and the duei coats of arms, is still visible today in the Arms Room of the castle. The current coat of arms comprises l'aquila and the fish symbols of noble family and the two calves with the lilies of Florence symbols of the family Vitelleschi.