“The Pantheon was built under Trajan’s successor, the Emperor Hadrian (AD 117–138), on the site of an earlier temple, which had been of an entirely different design but similarly dedicated to all the gods. . . . One passes from a world of hard confining angular forms into one of spherical infinity, which seems almost to have been created by the column of light pouring through the circular eye or oculus of the dome and slowly, yet perceptibly, moving round the building with the diurnal motion of the earth. . . .

The interior is substantially intact. The various types of marble, mainly imported from the eastern Mediterranean and used for the pattern of squares and circles on the pavement, for the columns and the sheathing of the walls—white veined with blue and purple (pavonazzo), yellowish-orange (giallo antico), porphyry and so on—still reflect and colour the light which fills the whole building.”

—Hugh Honour & John Fleming, from The Visual Arts: A History, 1982.