Manda Scott
The first novel in the series follows the life of Sebastos Pantera , the spy whose name means 'Leopard' as he comes in from the cold of a mission in Britannia to spy for the Emperor Nero at the time of the Great Fire of Rome . In subsequent books , Pantera faces his nemesis , Saulos ( aka Paul of Tarsus ) in "The Coming of the King" , dives deep into the loss of a legion's eagle in "The Eagle of the Twelfth" , ( the Twelfth Legion , apparently , did in fact lose their eagle , while the Ninth Legion , subjects of Rosemary Sutcliffe's "Eagle of the Ninth" , didn't ) and returns to Rome for the Year of the Four Emperors in "The Art of War" . 
<triplet> Eagle of the Ninth <subj> Rosemary Sutcliff <obj> author