One of our tours, the number 2, is dedicated to classical Rome and includes a visit to the Colosseum. The great excavations carried on in this colossal building in the years 1874 and 1875, have thrown an entirely new light on its history. These were made under the level of the ground, at the foot of the podium, which is the same as that of the original arena; this large level space had been indifferently called the ground, the floor, the stage, the area, or the arena; no one had any idea that the original pavement would be found 21 ft. below that level, and that the intervening space was filled with walls and passages, dens for wild beasts, places for lifts to send up men, and dogs, and animals: and canals for water, and several other contrivances for the use of the performers on the stage above, for practically the arena was the stage on which the performances took place. These excavations have enabled us to ascertain that this had been a boarded floor covered with sand, or arena (whence its name), and that this floor could be moved and replaced in a short time, at the word of the Emperor. The evidence of this is brought out clearly in the present work. Large corbels, or brackets, are provided for placing the boards upon when removed, and keeping them out of sight of the people in the galleries; they project from the wall below the podium, in the passage over the dens.We had all of us hitherto been taught that this enormous structure had been all built in ten years by the Flavian emperors ; this is the uniform modern history, but no ancient author says so. It is only one of the so-called “Roman Traditions”, which (as I am obliged to repeat continually) are nothing but the conjectures of learned men during the last three centuries, especially Panvinius and his school in the seventeenth.

From: The Flavian amphitheatre, commonly called the Colosseum at Rome: its history & substructures compared with other amphitheatres, John Henry Parker, 1876.