Quo Vadis: A Narrative of the Time of Nero by Henryk Sienkiewicz

"Quo vadis Domine" is Latin for "Where are you going, Lord?" and alludes to the apocryphal Acts of Peter, in which Peter flees Rome but on his way meets Jesus and asks him why he is going to Rome. Jesus says "I am going back to be crucified again", which makes Peter go back to Rome and accept martyrdom.