The strategy adopted by the Project was to use archeological investigation to narrow the range of dates that would need to be compared with the astronomical data. Although no archaeological traces of King Wu's campaign have been found, the pre-conquest Zhou capital at Fengxi in Shaanxi has been excavated and strata at the site have been identified with the pre-dynastic Zhou. Radiocarbon dating of samples from the site as well as at late Yinxu and early Zhou capitals, using the wiggle matching technique, yielded a date for the conquest between 1050 and 1020 BC. The only date within that range matching all the astronomical data is 20 January 1046 BC. This date had previously been proposed by David Pankenier, who had matched the above passages from the classics with the same astronomical events, but here it resulted from a thorough consideration of a broader range of evidence.