Ask Fr. Francis: What is the history of the veneration of relics? Why do Catholics believe in that?
Article “And, during the time the Church was persecuted, many of the martyrs were buried in the catacombs under Rome. Christians would visit them and venerate them. They would celebrate mass on top of their graves, and by befriending these saints through their relics, they received great graces and comfort to testify to their faith.”