Robert Prevost was brought to the Vatican in 2023 by Pope Francis as the powerful head of the office that vets bishop nominations, one of the most important jobs in the Catholic Church. On Thursday, he ascended to become Pope Leo XIV — the first American pontiff. Prevost, 69, had to overcome the taboo against a U.S. pope, given the geopolitical power already wielded by the United States in the secular sphere. The Chicago native is also a Peruvian citizen and lived for years in Peru, first as a missionary and then as an archbishop.