Original sentence: The English chronicler Geoffrey of Monmouth, who offered a genealogy of British kings that linked them to the Fall of Troy and whose twelfth century history is not considered a reliable source by modern historians, claimed that the Helena, Constantine's mother, was actually the daughter of "King Cole", the mythical King of the Britons
Edited sentence: The English chronicler Geoffrey of Monmouth, who offered a genealogy of British kings that linked them to the Fall of Troy and whose twelfth century history and is not considered a reliable source by modern historians, claimed that the Helena, Constantine's mother, was actually the daughter of "King Cole", the mythical King of the Britons