The discovery of the first papyrus in 1906 led to a shift in the degree of credence that historians assigned to the ancient sources of the period. In the 19th century, Xenophon, a contemporary of the events he described, was presumed to be universally preferable to the much later Diodorus Siculus. P was found to agree more with Diodorus's account than with Xenophon's on several key issues.