The bone-colored travertine of the Palazzo was spolia from the nearby ancient ruins of the Theatre of Pompey, for Rome was a field of ruins, built for a city of over one million that then housed a mere 30,000. The 44 Egyptian granite columns of the inner courtyard are from the porticoes of the theatre's upper covered seating, however they were originally taken from the theatre to build the old Basilica di San Lorenzo in Damaso. It is more probable that the form of the courtyard is derived from that of the Palazzo Ducale in Urbino, because the individuals involved in the early planning of the Palazzo had come from Urbino.