"From the map one can see that Copan is far to the southeast of the center of the Maya Old Empire. In the country beyond there are no other large cities with vaulted buildings and sculptured monuments. Yet there is about it nothing of the character of a frontier city. There are no fortifications to indicate that its relations with neighbors to the south and east were anything but friendly, and there is little in its art which suggests foreign influences. If anything, the art of Copan surpasses that of the Petén and is strikingly individual, as if the city were itself the nucleus of a cultural subdivision of the Old Empire. In most Petén cities architectural decoration was executed in stucco, and sculpture is largely confined to stelae and altars, whereas at Copan stone carvings, often in full round, adorned every important building.
As if jealous of this superb creation of man, all the most violent forces of nature seem to have conspired to destroy it. Even in historic times, earthquakes have shaken the ruins, and now the beautifully carved fragments of its buildings lie scattered on the slopes of its pyramids like the pieces of a gigantic jigsaw puzzle in stone. The Copan River has wantonly changed its course to gnaw at the east side of the Acropolis. It has devoured entire several buildings and has washed away thousands of tons of stone, leaving exposed a vertical cut a hundred and eighty-five feet in height. Seen thus in section, ancient plaza floors and the remains of partially dismantled walls, covered by layer upon layer of later construction, testify to untold centuries of human effort."
Tatiana Proskouriakoff, An Album of Maya Architecture, p. 31