"The notion of the Perserschutt, generalized from the deep stratigraphy alongside the Parthenon to almost anywhere on the Acropolis, proved to have an enduring appeal. The year 480 became a watershed in the history of Greek art, the archaic before that date, the early classical after. The watershed, moreover, was not merely a change in style; it was a change of spirit. One of the more authoritative students of Greek Art, Martin Robertson, Lincoln Professor of Archaeology emeritus at Oxford, wrote in his general study of Greek art published in 1975."
The Hand of Daedalus, ch. 2, R. Ross Holloway
Die Ausgrabung der Akropolis vom Jahre 1885 bis zum Jahre 1890 [excavation report published in 1906 in Greek and German]