Mustard gas was said to have been used as early as the Battle of the Somme. Mustard gas was first deployed a year after at the Battle of Ypres.
The rifle found in the Amiens cathedral is of a type not manufactured during the Great War.
When Karim investigates a dead soldier, he describes the corpse as lying in a 'pool of cold blood.' The corpse and the ground its laying on however are completely clean.
Ms. Roivas is called, with the caller saying that her grandfather had an accident. What happened to him clearly was no accident.
The Latin spoken by the Roman soldiers is improperly pronounced.