Peter tried his best to spread the gospel in Rome in his later years. Because of his earnest preaching, many people abandoned their idols and turned to the true God. It is said that Peter used the "underground tomb cave" on the outskirts of Rome as a missionary place to avoid attracting the attention of the Roman government. Later, the tyrant Nile persecuted him and arrested Peter. According to Clemens and Irene, Paul and Peter were martyred in Rome almost at the same time. Tertullianus was the first godfather to mention that Peter was crucified, and Olkin further mentioned that Peter was crucified.