These four historical maps nicely illustrate the four crucial treaties that transitioned from the old Frankish-Merovingian (post Western Roman Empire) into the modern states of France and Germany, during the 9th century.
Verdun, 843, was the division of the old Merovingia - but by the Treaties of Mersen and Ribemont the modern States are emerging.

Lotharingia, now Lorraine, went to Germany, but France always felt the Rhine should be the common frontire, with Lorraine going to France.
Charles, Louis II, Lothair, -  thank you ever so much for setting the scene for WW1 and WW2 some 11 centuries later.....

http://fooddeserts.org/images/000FraGermany.htm - see year 864.

http://fooddeserts.org/images/FraGermanyImage001.jpg

Dr Hillary J. Shaw
Director and Senior Research Consultant
Shaw Food Solutions
Newport
Shropshire
TF10 8QE
www.fooddeserts.org