The Catholic Church doesn't "make" someone a saint the way a studio makes someone a movie star. If a person lives a life of heroic virtue, and miracles are attributed to that person, and they have passed away, they are eligible for the process of being declared a saint. The stages before sainthood are "Servant of God", "Venerable", "Blessed" and finally, with the consent of the pope, "Saint".
So what does all of that mean? It means that at the time of their elevation to sainthood, the Catholic Church agreed that the deceased were spiritually upright, did good things in the world and performed a miracle. It means that at that time, the saint in question was the sort of person the Catholic Church felt the world needed as a model for its behavior. It means the saint embodied the best of humanity, in that age.
Every saint is in some way a commentary on the society they lived in. Saints' deaths are often terrible, and symbolic of the sacrifices they made in life. Saints are still people, and like all people, they have their flaws, their sins and their private conflicts. How well do you know your Catholic saints? Find out, with this quiz.