A number of people with different religious beliefs have severally declared that pope is not a Christian. Most of the people who have made these claims are people who have been know to run cults.
Pope Julius I
In 1749 Pope Benedict XIV declared the Roman Colosseum to have been sanctified by the blood of Christian martyrs.
Today the attending physician makes that determination. However, the camerlengo will still call the Christian name of the pope three times and, if there is no response, will declare that the pope is dead.
Pope John XIIII declared the 2000 Jubilee Year.
The pope has always been a Christian.
Pope Julius I
Pope John Paul II declared Juan Diego a saint.
The pope became a Christian at the time of Saint Peter the first pope.
Pope Gregory VII was a Catholic pope. Of course he was a Christian.
Otto I got declared the Roman Emperor because he helped the Pope when he was struggling so the pope declared him the Roman Empire.
He was elected as pope on April 19, 2005.
The Pope