The building consisted of five parts - a basement or podium, a pteron or enclosure of columns, a pyramid, a pedestal and a chariot group. The basement, covering an area of 114 ft.
The pteron consisted (according to Pliny) of thirty-six columns of the Ionic order, enclosing a square cella.
From the portions that have been recovered, it appears that the principal frieze of the pteron represented combats of Greeks and Amazons.
Above the pteron rose the pyramid, mounting by 24 steps to an apex or pedestal.