The basilica contains the largest extant hall from classical antiquity (see List of ancient Greek and Roman roofs).

[4] The Aula Palatina generally follows the standard architectural plan of earlier basilicas, with a lack of columns in the interior and an open, box-like shape.

In the 17th century, the archbishop Lothar von Metternich constructed his palace just next to the Aula Palatina and incorporated it into it doing some major redesign.

Later, in the 19th century, Frederick William IV of Prussia ordered the building to be restored to its original Roman state, which was done under the supervision of the military architect Carl Schnitzler.

When it was repaired after the war, the historical inner decorations from the 19th century were not reconstructed, so that the brick walls are visible from the inside as well.