Cardinal Rodrigo Borgia gave it the form it now has, rebuilding the castle and enlarging the two great towers inside the walls, the larger of which is round and the smaller square.

Later the castle was restored and furnished with bastions by Paul III and his son, Pierluigi Farnese, the first Duke of Castro and Nepi.[80] In 1500 this castle was as strong as that of Civitacastellana, which Alexander VI rebuilt.

Unfortunately, it is now in ruins.

The remains of the castle-palace and all the outer walls are covered with thick ivy.
Time has spared nothing but the two great towers.
On the side toward the city the ruined stronghold is entered through a gateway above which is inscribed in the fair characters of the Renaissance, YSV VNICVS CVSTOS.

PROCVL HINC TIMORES.YSV.This leads into a rectangular court surrounded by walls now in ruins.