Some historians doubt the existence of the Xia dynasty. What does this say about historians? Historians look for trustworthy accounts, and they do not trust texts written before 100 CE. Historians require physical evidence. No artifacts have been found that are definitively from the Xia dynasty. Historians look at geographical and climate evidence. The Huang He has never flooded, which makes the legend of Yu the Great impossible. Historians require physical evidence. No artifacts have been found that date to before 1600 BCE. Historians look for evidence from written records. There are no texts from the time of the Xia dynasty.