The Lost Testament: A Bronson Novel (Chris Bronson);

A single sheet of parchment, with the power to bring down an emperor and raze an empire. For seventeen centuries the scroll lay hidden away in the vast Vatican archives, guarded by a select, ruthless few who knew of its destructive potential—and would swiftly kill to contain its secrets.
 
When the parchment mysteriously turns up in the stall of a murdered Cairo market trader, authorities contact the British for assistance in identifying the document. Police detective Chris Bronson and historian Angela Lewis arrive in Egypt to take on the case, but quickly find themselves as targets, pursued by assassins. Stalked across North Africa and Europe, Chris and Angela must decipher the parchment’s tantalizing message before their time runs out.