In order to understand the fall of the Western Zhou, it is important first to establish a reliable chronology of events that happened in the eleven years of the reign of King You. This chronology will help us not only to understand the political changes at the Zhou court, but also to correlate them with the historical happenings in some of the regional polities. The most important chronological account of King You's reign is found in the Current Bamboo Annals. As already said in the introduction, after the text on the bamboo strips was excavated in ad 281 in northern Henan, its entries were quoted extensively by the medieval writers in their works, especially their commentaries on the transmitted texts. Since the Current Bamboo Annals was declared a fake by most Qing authorities, starting with Zhu Youzeng in late Qing, the fragmentary quotations were retrieved from the various texts and their commentaries to reconstruct what is supposed to be the “original text,” the Ancient Bamboo Annals. As far as the eleven years of King You's reign are concerned, there are a number of discrepancies between the Current and Ancient versions, discrepancies that have contributed in part to the reasoning accusing the Current Bamboo Annals of being a later forgery. The issue certainly concerns not only the political history of the last Western Zhou reign, but also the authenticity and historical reliability of this critical ancient text; therefore, a separate analysis is necessary here.