At a special ceremony in Rome tomorrow, Pope John Paul II will preside over the canonisation of Father Josemaría Escrivá, the founder of Opus Dei. The order, which has grown since his death to 85,000-strong worldwide, has acquired a special influence with the Pope, who established it as a personal prelature, bestowing on it an autonomy which no other lay-dominated Catholic organisation enjoys.
Founded in Spain in 1928 Opus Dei is dedicated to the preservation of traditionalist teachings, a life of prayer and penance, and the idea that the lay can aspire to holiness without joining the priesthood. It has cast its net predominantly among the wealthy and influential in society, leading many to accuse it of elitism.
Many Catholics are critical of the canonisation, concerned about the order's secret influence, its deep conservatism, its allegedly cultish recruitment techniques, and Father Escrivá's one-time links with the Franco regime.
And they also point to what they see as a disturbing pattern in the elevation by Pope John Paul of the most conservative and traditionalist of role models for the Church.
Many are also concerned at the numbers involved - some 462 canonisations since 1978 - and the fast-track approach that the Pope instigated in 1983 which some say has debased the currency. Father Escrivá died in 1975, and his elevation tomorrow is among the fastest in history.
The canonisation comes just days after the Vatican announced that it has approved a miracle attributed to Mother Teresa and will allow her beatification to be processed, only five years after her death.
If the Pope, who allowed the beatification process to start only two years after her death instead of the usual five, signs the decree approving the miracle, probably in December, a beatification ceremony can be held next year. Not since Francis of Assisi was canonised two years after his death in 1228 has the process been so fast.
Yet the beatification of Pope John XXIII, the most popular pontiff in the 20th century, took from his death in 1963 to 2000.
Tomorrow's ceremony will be an important and deeply moving day for many millions of Catholics. But it will also be an important message from an ageing, deeply conservative Pontiff to the faithful and the world that he will continue to fashion his Church as he sees fit and in his image.