This fortress which stood at the entrance to
Vatican for centuries was begun by Hadrian around 128 as a mausoleum
for him and his family. The mausoleum was finished in 139 and Hadrian
and many succeeding emperors were buried here. By the 6th century the
building was gradually transformed into a castle and it was used to
protect the popes for nearly 1000 years. According to legend the
name of the castle was given during the plague of 590 when Pope Gregory
the Great who was passing nearby had a vision of an angel sheathing
his sword atop the stone walls.
In front of the castle stands Ponte Sant'Angelo (Bridge of Angels)
which was built by Hadrian as a suitable approach to his mausoleum.
The bridge was transformed by Gian Lorenzo Bernini who designed
the ten statues of Angels.