Florence of Worcester based his 'Chronicon ex Chronicis' on a universal chronicle by Marianus Scotus. Into this, however, he interwove a large amount of additional information from English sources. One of the sources used was a, now lost, version of the Anglo-Saxon Chronicle. Although the 'Chronicon ex Chronicis' is traditionally attributed to Florence, and has an entry for 1118 which reads :
"On the nones of July (7th), Florence of Worcester, the monk, died. His deep knowledge and great industry have rendered this chronicle of chronicles preeminent over all others."
it seems possible that it's author was actually John of Worcester, who, in the traditional view, merely continued the work after Florence's death. The Anglo-Norman chronicler Orderic Vitalis, who visited Worcester and saw John's work, writes:
"John, an Englishman by birth who entered the monastery of Worcester as a boy and won great repute for his learning and piety, continued the chronicle of Marianus Scotus and carefully recorded the events of William's reign and of his sons William Rufus and Henry up to the present... John, at the command of the venerable Wulfstan [d.1095] bishop and monk, added to these chronicles [of Marianus Scotus] events of about a hundred years, by inserting a brief and valuable summary of many deeds of the Romans and Franks, Germans and other peoples whom he knew."
Orderic Vitalis translated by Marjorie Chibnall
'The Chronicle of Florence of Worcester' edited and in part translated by Joseph Stevenson