The morning «salutatio» (greeting) was the moment when the emperor received those who asked for an audience. For the Senators, this official meeting with the emperor was an event of great political importance. It is probable that only the members of the highest classes of Rome were received in the Aula Regia and the adjacent Basilica.
The ancient writers describe a hierarchy consisting of «amici» (friends), in other words a restricted circle of people who were particularly close to the emperor, and of other less important groups including the «inferiores». We have only a few descriptions of this ceremony: Domitian behaved with disdain to everyone and demanded that the senators knelt before him to kiss his feet, following the Eastern tradition. Later emperors, for example Trajan, used instead to embrace or call by name the people they received at the audiences.
The Aula Regia was huge (1118 square metres) and sumptuously decorated with coloured marbles and colossal statues, placed in the niches along the walls. Two of these, a seated Heracles and a Dionysus, still exist today. The throne of the emperor used during official meetings was placed in the apse at the end of the Aula. The adjoining basilica was smaller, again with an apse, but divided into naves by two rows of columns.