The "cenatio" or Banquet Hall is on the southwest side of the peristyle and is the 2nd largest room in the Palace. Like the "Aula Regia", it was extravagantly decorated, with several tiers of columns in exotic marbles and a frieze. From the "cenatio" guests could look out through large windows onto the peristyle lake and fountain or onto two courtyards at the sides with elaborate oval marble fountains surrounded by yellow Numidian marble columns. The centre of the southern wall of the hall has an apse surrounded by two passages which allow access to the library of the temple of Apollo. The floor of the hall is covered with marble dating from the early 4th century though the hypocaust beneath dates from the 120's (Hadrian). This heating system suggests that this hall served as a banqueting hall in the winter and has been identified with the "Cenatio Iovis" mentioned in ancient literary sources.