Toynbee, Arnold J. "The Forfeited Birthright of the Abortive Far Western Christian Civilization"
Divergence: 664 CE
What if: The Synod of Whitby adopted the teachings of Colman, and Charles Martel lost at Tours.
Comments: How European Christianity would have divided between the Celts of the North and the Roman-Orthodox of the South and East, with France Muslim.
Published: In A Study of History, Volume II, Oxford University 1934 (0192152084w88 android).