Whether or not viva la vida is an alegory or not, no one will know except for coldplay. I don't believe it is about christ. Throughout his life, he was glorified by some and refused by others. He never had a trend from power to no power, and vice versa. I believe the most important line of this song is "who would ever want to be king?" the man in this song is generally prideful of his power. Before its too late, the man realizes what hes depending on to remain in power. Eventually, his pride leads to revolution until almost everyone despised him. Notice in the chorus it switches from past tense to present tense. This shows that this is when he has no power. The words such as Saint Peter could represent that he is hoping from some compassion to redeem himself from the prideful things he has done. Although he has no idea why anyone would ever forgive him, he hopes for it to occur. More or less, it is a lesson on both pride and forgiveness, depending on who you are in a situation like this. Crticize it all you want, but this is how I feel about this song.