Visible all along Viale del Policlinico are the northern and eastern limits of Castro Pretorio. Beyond the wall is the Castro Pretorio Barracks, founded by Pius IX and seat of the Italian cavalry after the proclamation of Rome as capital city. On this spot, the northern gate of the single-arched Castro is visible. In 1960, a survey of the masonry brought to light parts of the gate dating back to the time of Tiberius: a section of the arch made of sesquipedali (bricks of approx. 45 cm), two travertine bollards and two pillars made of excellently crafted opus latericium or brickwork. The upper section, characterised by three large windows and made of tuff and brickwork, was built later in place of the original gable attic. The northern gate was closed when the Castro Pretorio was incorporated into the Aurelian Wall.
