The process by which a person is declared a saint can start only after they have died and normally there is at least a five-year gap.

Once it starts, it can take a a few years to move through the stages to sainthood, or it can take centuries.

The Roman Catholic Church believes that God works miracles through intercessionary prayers through people in heaven.

In the first stage, a “cult” must be established which allows a “cause” to be set up in Rome. An investigation is made into the life of the individual and the results sent to Rome. If he or she is judged to have lived a life of exemplary holiness, they are declared “Venerable”.

For someone to be proclaimed “Blessed”, a miracle of physical healing must be approved by panels of doctors and theologians.

The doctors have to rule that the healing is scientifically inexplicable, while theologians examine whether it occurred as the result of the intercession of the person whose beatification is being considered.

If the doctors and theologians judge the case positively, it is then examined by the Cardinals and Bishops of the Congregation for the Causes of Saints. The results of these discussions are communicated to the Pope who alone can declare a healing to be a true miracle. Only when all these stages have been successfully completed does the Pope authenticate the miracle.

A second miracle has to be recognised for a person to be canonised, or declared to be a saint.

In the case of martyrs, their deaths alone for the sake of their faith suffices for them to be canonised.