How did Elizabeth Ann Seton become a saint?

Elizabeth, a few years after her death, would have a case for canonization opened locally with the bishop. They would submit documents and interview witnesses to see if she had lead a life of heroic virtue that would qualify her to be given the title of saint. The results of the study would have been submitted to the Sacred Congregation for the Causes of Saints in Rome. If they agreed with the findings, the information would be submitted to the Pope who would then have declared her a Servant of God, the first major step towards canonization. Now an official cause has been established.

More investigations would be done and, if they pass muster, the pope could then name her as Venerable. This was done on 18 December 18, 1959, by Pope John XXIII.

For the third stage, more investigations are required for Beatification. In addition, at least one miracle must be verified that was done through the intercession of Venerable Elizabeth Ann Seton. Once all this is completed and verified, the pope can then name her as Blessed Elizabeth Ann Seton. This was done on March 17, 1963, by Pope John XXIII.

The final major step, canonization, requires more study as well as an additional miracle that has been verified. The final report was then submitted to Pope Paul VI and he officially canonized her as a saint on September 14, 1975.

This process can take many years, sometimes even centuries to complete.