Probably built in the late 16^th century on the ruins of Nero's and Alexander's baths, it was radically altered by its Spanish owners who heightened the building and made other renovation works in the course of the two following centuries. In 1933, after a long series of changes of ownership and consequent further reorganisation works, it became the barracks of the policemen detailed to the Senate.

Finally, it was purchased by the State in 1980 and transferred to the Senate.

Senators' offices are now located there.