 One difficulty in dating the proto-Parthenon is that at the time of the 1885 excavation the archaeological method of seriation was not fully developed; the careless digging and refilling of the site led to a loss of much valuable information.An attempt to discuss and make sense of the potsherds found on the Acropolis came with the two-volume study by Graef and Langlotz published in 1925–33.This inspired American archaeologist William Bell Dinsmoor to attempt to supply limiting dates for the temple platform and the five walls hidden under the re-terracing of the Acropolis.