John XV began the first official canonization process, before which sainthood was only granted through common belief. Saint Ulrich of Augsburg became the first official canonized saint, followed by more than 10,000 saints through the centuries.
Through canonization, the Catholic Church developed a much stricter regulation process to ensure that saints deserve the title and fully embody the messages of the Church. This process includes four steps: the request for canonization, determination of the candidate's virtues, beatification and canonization. Candidates can become beatified if they were martyred or if their intercession was associated with a miracle. Full canonization requires another miracle. If candidates cannot meet either of these final two steps but the Church determines them to be fully virtuous and deserving, they are granted the title of "Venerable."
Outside of the canonization process, many Catholics unofficially consider saints before St. Ulrich the first saints of Christianity. For example, St. Stephen, known for being the first Christian martyr, lived around eight centuries before St. Ulrich. In addition, St. John the Baptist, St. Joseph and St. Dismas lived during Jesus' lifetime, but none of them were officially canonized. One of the most well-known and recently canonized saints is Pope John Paul II, whom Pope Francis canonized in 2014.