 Complete the following phrase:  The Chronicle of 754 covers the years 610 to 754, during which it has few contemporary sources against which to check its veracity. It begins with the accession of Heraclius and is considered an eyewitness account for the Umayyad conquest of Hispania. Some consider it one of the best sources for post-Visigothic history and for the story of the Arabian conquest of Hispania and Septimania; it provided the basis for Roger Collins, The Arab Conquest of Spain, 711-797, the first modern historian to utilise it so thoroughly. It contains the most detailed account of the 