"...the Stoa of Attalus...is a two-storey building, 116 m x 19.4 m (381 ft x 63 ft 8 in), with a Doric colonnade on the ground floor, and an Ionic upper colonnade incorporating a balustrade. All the faŤade is in marble. The inner ground floor colonnades are equal in height to the exterior to support the floor above, but at double spacing they are Ionic. The inner colonnade of the upper floor has columns of palm-leaf design developed in Pergamum. There is a row of rooms behind the colonnades on both floors. The details are unsatisfactory, in comparison with the forms of Classical Athenian architecture. More important is the way the stoas are used to close off the agora to a regular plan."

— Sir Banister Fletcher. A History of Architecture. p147.