What is “canonization”?

The story behind the answer

It’s the Church’s formal process that ends with universal recognition of a holy person, permitting public veneration throughout the Catholic world. Investigators gather evidence of heroic virtue and posthumous miracles; after beatification, further confirmed miracles are typically required before the pope issues the final decree.

In the Middle Ages this process was centralized: local cults of saints were common early on, but in 993 Pope John XV pronounced the first papal canonization (St. Ulrich), and by the 12th–13th centuries popes like Alexander III and Gregory IX reserved the right to canonize. This helped standardize criteria and shape models of sanctity for Christendom. Not to be confused with canon law (church legislation) or a cathedral canon (a clergy office).