There are certain elements of the book of Esther that are historically accurate. The story told in the book of Esther takes place during the rule of Ahasuerus, who amongst others has been identified as the 5th-century Persian king Xerxes I (reigned 486–465 BC). The author also displays an accurate knowledge of Persian customs and palaces. However, according to Coogan, considerable historical inaccuracies remain throughout the text, supporting the view that the book of Esther is to be read as a historical novella which tells a story describing historical events but is not necessarily historical fact. Edwin M. Yamauchi has questioned the reliability of other historical sources, such as Herodotus, to which Esther has been compared. Yamauchi wrote, " was, however, the victim of unreliable informants and was not infallible." The reason for questioning the historical accuracy of such ancient writers as Herodotus is that he is one of the primary sources of knowledge for this time period, and it has been frequently assumed that his account may be more accurate than Esther's account.